What Kaley Cuoco's Costars Have Said About Her

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Kaley Cuoco's been acting since she was a kid, and by all accounts, she's bonded with a number of her costars over the course of her long career. She's been candid about her friendships with Jim Parsons and Zosia Mamet, and she's been transparent about the ups and downs she and Johnny Galecki have gone through. And yes, it's a two-way street: A number of Cuoco's costars have also spoken about their experiences working with her and what their behind-the-scenes relationship looks like. 

It may seem like Cuoco hits it off with just about everyone she works with, but in reality there's been at least one fellow actor she didn't get along with. As Cuoco said on a 2026 episode of "Armchair Expert," she sensed that Rose McGowan might've not been thrilled about her joining "Charmed" in its final season. "Rose, maybe not as happy. I don't know," she said. "I still don't know if she liked me."

While McGowan's true feelings about her may forever remain a mystery, a number of Cuoco's other colleagues have made it clear how they feel about her. Here's what Kaley Cuoco's "8 Simple Rules," "The Flight Attendant," and "The Big Bang Theory" costars have said about her over the years.

On the "The Big Bang Theory," Sheldon Cooper (Jim Parsons) and Penny Hofstadter (Kaley Cuoco) were a classic example of "opposites attract." While their connection was platonic, not romantic, they had a strong bond. In the 16th episode of the 8th season, Sheldon and Penny put their connection to the test by doing an experiment to see if they can fall in love. During the activity, Sheldon tells Penny, "I suppose I do think of you as a sister and sometimes a mother." It sounds like Jim Parsons felt that way about Kaley Cuoco in real life, too.

In 2022, after Cuoco announced she was expecting her first kid, Parsons told Entertainment Tonight he had no doubts that his former costar would make a great mom. "She was ... a mother-like figure to me for many years on 'Big Bang,' even though I'm tremendously older than her," he shared. He added, "She's a very warm person. I think that child is lucky to have her for a mother."

Parsons has also praised Cuoco's acting chops. In "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series" by Jessica Radloff, Parsons praised Cuoco. "I don't know that anybody on the show has a greater ease with comedic timing than she does," he said. "And I never saw her with a script in her hands. I was like, How are you doing this?! I mean, it was unbelievable to me!" He also went on to talk about Cuoco's performance in the series "The Flight Attendant." "There's just a confidence and a joy that comes together to give her this ease," he explained.

Johnny Galecki, who played Leonard Hofstadter on "The Big Bang Theory," is one of the men Kaley Cuoco has dated. They were together from 2008 to 2010, and luckily, they didn't end their relationship on bad terms. Rather, they stayed friends — they kind of friends who joke around with each other on social media, no less. In 2021, for example,  Cuoco shared a Valentine's Day post for then-husband Karl Cook on Instagram (via Business Insider), writing, "I don't remember a moment before you entered my life.. what a boring life that must have been!" On the post, Galecki commented, "Um," and Cuoco replied, "LOL." They even teamed up for a Royal Kingdom mobile app ad where they brought in their "The Big Bang Theory" energy.

There are tidbits of what Johnny Galecki and Kaley Cuoco's relationship was like in Jessica Radloff's book "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series." Galecki recalled getting in his head before shooting more emotional scenes, only for Cuoco to say to him, "You got this." "Next take I'd nail it. You need to have that," Galecki said.

In the same book, Cuoco remembered the support she and Galecki showed one another. "We would always have each other's back," she said. In response, Galecki said, "Kaley was my rock. I knew everything that we talked about was from the truest of our hearts." He also celebrated her craft, noting that she has an effortlessness about her. "Whatever Kaley's process is, or sometimes lack thereof, she knows exactly what will make things shine and pop, just by her own instincts. She's an anomaly."

On "The Big Bang Theory" set, Kaley Cuoco was known for learning her lines faster than anyone else in the cast. In "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series," Johnny Galecki recalled how Simon Helberg, who played Howard Wolowitz, described Cuoco's memorization skills: "As Simon said once, she doesn't even open a script, she just puts her hand on top of it and by osmosis absorbs it, and it's amazing."

That wasn't the only thing Helberg noticed about Cuoco. In the aforementioned book, Helberg spoke about how unflappable she appeared to be no matter the circumstance, and how much he envied the calm, cool, and collected way she carried herself. "I remember when Kaley was getting her star on the Hollywood Walk of Fame and she said, 'This is like the second time in my life I've ever been nervous,'" Helberg shared. "I thought she was kidding, but no. I say that not in a disparaging way, but I couldn't be more jealous." Now, this is not among the big controversies that completely rocked "The Big Bang Theory" cast, but it is something.

Kunal Nayyar has had an awesome transformation over the years. That said, there's one thing that might not have changed: his bond with Kaley Cuoco. Nayyar, who played Raj Koothrappali, basically sees her as his kin. After Cuoco got married to her now ex-husband Ryan Sweeting in 2013, Nayyar said as much in a 2014 interview with People: "Kaley is like a sister to me. You become so close over such a long period of time. It's like your family member getting married."

In "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series," Nayyar reflected on what went through his mind when he first met Cuoco. Though he is five years her senior, he remembered looking up to her. At the time, she was already an established TV star in the United States, whereas "The Big Bang Theory" was Nayyar's breakout role. However, it didn't take long for him to feel at ease around her. "She had a real unintimidating bubbliness about her," he said.

Nayyar also was blown away by the acting choices she made on the show. Looking back on Penny and Sheldon's aforementioned charming dynamic, Nayyar said, "Kaley as Penny had this really sweet laugh or even a look that she would do when Sheldon was just being Sheldon. It was so disarming and endearing and nonjudgmental. It's something I had never seen on television — that kind of relationship."

On "The Big Bang Theory," Amy Farrah Fowler, played by Mayim Bialik, slowly grew on Kaley Cuoco's Penny Hofstadter. In real life, though, there were many rumors about whether or not Cuoco and Bialik were actually on good terms. Though the rumors were never confirmed, there were rumblings about Bialik and Cuoco potentially being at odds over the latter's salary. However, in a 2020 video for Wired, Bialik tried to put said rumblings to rest. "We worked together for nine years. Then I went to her wedding and celebrated things with her," she said. "I would say we're friends."

In "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series," Bialik spoke about how she and Cuoco clicked over their shared love of animals. "I always had questions about her horses and her dogs! So just like in a family, you find ways to connect," Bialik said. What's more, in 2014, Bialik told Variety that Cuoco was her go-to person when it came to social media. As Bialik put it, "[Cuoco] had her finger on the pulse of things I didn't even know existed, so she was the person I learned so much about social media from."

When you start working at a new place, it's always nice when your new colleagues are welcoming. Just ask Melissa Rauch, who played Bernadette Rostenkowski-Wolowitz on "The Big Bang Theory." In "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series," Rauch said that when she first joined the cast, Kaley Cuoco was one of the stars who was quick to make her feel right at home. "Kaley invited me to join her at spin class, which was really cool," Rauch recalled. 

In the aforementioned book, Rauch also shared some of her experiences filming with Cuoco. She talked a bit about Season 9, Episode 11, "The Opening Night Excitation," where Sheldon reveals his explicit plans for Amy's birthday to Penny and Bernadette. "I can picture both Jim's perfect delivery of the coitus line and Kaley's perfect deadpan expression as she breaks that glass," Rauch recalled. "It still cracks me up." We can relate, can't we? 

In that same episode, Penny and Bernadette give Amy a heads-up about Sheldon's birthday plans, and that scene also stuck with Rauch. "I also remember sharing a look with Kaley when Mayim hit that waxing line — 'Let's go get me waxed!' — out of the park," she said.

Beverly Hofstadter, mother of Leonard Hofstadter, wasn't exactly the lovey-dovey kind of mom. What's more, she and Penny Hofstadter didn't seem to have anything in common. While Penny was super chilled out, fun, and sometimes even impulsive,Beverly was, well, the opposite of that. So when the two characters clicked, it was especially endearing.

The actor who played Leonard's mother, Christine Baranski, spoke about Season 3, Episode 11, of the show in "The Big Bang Theory: The Definitive, Inside Story of the Epic Hit Series." "Kaley and I had a bar scene in season three where we got drunk. And it was so wonderful. Well, wonderful/terrifying because they rewrote the scene while we were on set," she said. "In between takes, Kaley and I just bonded."

If you enjoyed Beverly and Penny's unexpected connection on the show, you might be happy to know that so did Baranski. "Later in the series, there was this girlfriend relationship between Penny and Beverly, and that to me was just so great," she said in the aforementioned book. "There were so many one-liners that I just thought were so pissingly funny. And so many touching moments."

Kaley Cuoco has had a beautiful transformation that includes rising to fame on the sitcom "8 Simple Rules" and then becoming a bona fide star on "The Big Bang Theory." She has gained many fans over the years, including actor and comedian Kevin Hart.

Cuoco and Hart worked together in the 2015 comedy "The Wedding Ringer," and then again in 2022's "The Man from Toronto." In a 2021 interview with Vanity Fair, Hart said, "I was, of course, aware of Kaley and her talent, just because of her success in TV. So when I found out that we had an opportunity to cast her in 'The Wedding Ringer,' and meeting her, she was exactly what I thought she would be, just extremely personable, great energy, and just a fun, fun spirit."

In the same Vanity Fair interview, Cuoco talked about how she recorded her self-tape for "The Man from Toronto" while shooting the series "The Flight Attendant." Hart was impressed that she auditioned like anyone else would rather than reaching out to him directly, despite the fact that they'd worked together before. "This is what I think says a lot about her as a person," he said.

Zosia Mamet and Kaley Cuoco were both in "The Flight Attendant." In the show, their characters were close friends. It didn't take long for the actors to actually hit it off in real life. They not only lived together for a bit while filming the series, but got matching tattoos. Talk about friendship goals.

In a 2022 interview with Marie Claire Australia, Mamet spilled the beans about her and Cuoco's relationship. "Kaley is an epic human and we got, almost annoyingly close. I'm literally at her house right now. I live in New York, but I'm staying with her while we're out doing press, so we're basically a married couple," she said. Back in 2021, Mamet also posted cute pictures on Instagram for Cuoco's birthday. In the caption, she called Cuoco a "magical unicorn human," adding, "You are one of a kind @kaleycuoco I love you more than words could ever say."

In the previously mentioned Marie Claire Australia interview, Mamet also didn't hold back while complimenting Cuoco's work on "The Flight Attendant." "[Cuoco is] an exceptional human being and an exceptional captain," Mamet said. "She watches out for everyone and I've never seen anyone multitask the way that she does." It doesn't seem like they're the all work and no play kind of friends either. As Mamet said, the two of them and costar Deniz Akdeniz had such a good time making "The Flight Attendant" together that they'd get lost in scenes. "[W]e have to be told to wrap it up and remember that we're making a TV show," she said.

On the first two seasons of "8 Simple Rules," sitcom legend John Ritter played the role of Kaley Cuoco's character's dad. In real life, the two developed a sweet father-daughter bond while working together. During a 2025 talk with People at The John Ritter Foundation Evening from the Heart Los Angeles Gala, Cuoco shared that Ritter went into protective dad mode the very first time they met. She recalled, "I was 16 when we did our first table read, and I was playing the 'sexy' sister. And so, I remember I wore a very revealing dress to our table read." Ritter, however, was not on board with this ensemble, and acted accordingly. "He took his jacket off and put his jacket over me and he said, 'You'll never dress like that again, missy.' That was the first thing he ever said to me, and he instantly became my TV dad,'" she said.

Ritter died in 2003 at the age of 54. The "Three's Company" legend left the "8 Simple Rules" set for the hospital because he wasn't feeling well, and he died hours later. Before he left the set, Ritter dropped by Cuoco's dressing room. As Cuoco recalled in the documentary "Behind Closed Doors: John Ritter" (via Entertainment Tonight), "He goes, 'I love you,' and I was like 'I love you too, silly man.'" She added, "He goes, no, I want you to know I love you." After this, Cuoco remembered saying she loved him too, and they shared a hug.

Rosie Perez is not a fan of flying — so much so, she almost passed on the chance to join the cast of "The Flight Attendant." However, Kaley Cuoco literally convinced her to change her mind. In a 2020 interview with Collider, Perez shared that Cuoco ultimately convinced her to take the role. Not only did Perez and Cuoco get along instantly, but Perez went on to tell her manager, "Oh, my god, I'm in love with this girl [Kaley Cuoco]." So much so, Perez was determined to work with Cuoco — yes, even if that meant playing a member of a flight crew: "I've gotta do ['The Flight Attendant']. I have to do this. I've gotta get over my anxiety of flying."

It seems the experience of working on the series did not disappoint. During the same Collider interview, Perez shared that Cuoco, who also was an executive producer on the show, was a great leader. "She just stepped back and let everyone do their thing, but yet you knew she was also in charge," Perez said. "When she had to be in charge and she had to be the heavy hand, she didn't shy away from it, and she did it with such dignity and such fortitude. In a 2021 interview with The Hollywood Reporter, Perez praised Cuoco's acting instincts, noting that she's a quick and natural scene partner. "The good thing about Kaley is, whatever you throw at her, she has the racquet in hand and she's ready to hit the ball over the net right away," she said.