Britney Spears' Surprising Pop-Rock Cover

Britney Spears has long been known for her pop princess status, never straying far from her signature catchy bops. But that doesn't mean Spears' musical style is all one note. She's come a long way since her first single "...Baby One More Time" in 1998, experimenting with sultrier sounds and sexier themes as she's grown older.

Still, Spears was never one to try genres other than radio-friendly pop — and that's okay, considering pop has always allowed her a chance to showcase her youthful voice and natural dance abilities on stage. The singer has consistently stayed true to her pop roots, ever since her stint as a Mouseketeer.

However, there was one pop-rock cover that seemed to show off Spears' musical range and an edgier side to the Princess of Pop. It's a cover that even some of Spears' biggest fans may have missed when looking back on her decades-long singing career.

In 2009, soon after Britney Spears' conservatorship began (per Billboard), the singer was on tour promoting her new album "Circus." During the tour, she gave an unexpected performance covering Alanis Morissette's "You Oughta Know," a song that came out in the mid '90s, before Spears became a household name and when alt rock still reigned in the world of music.

While the original video seems to have been taken down, some evidence of the cover remains on YouTube. The performance was a departure from Spears' usual style, proving her varied musical and singing abilities. She seemed to use a deeper voice, which rumor has it is her "real" voice that she was forced to change when trying to make a name for herself as a singer (via The U.S. Sun). What's more, according to Entertainment Weekly, Spears appeared to sing the cover live, with no recording, making it an especially raw and authentic performance.

Years later on Andy Cohen's show "Watch What Happens Live," Morissette gave her opinion on the performance, calling it "awesome." With reports of a tell-all book by Spears on the way, maybe we'll be seeing more of the angsty and honest Britney in the near future.