But she's about to drop her first-ever solo album.
The 35-year-old singer, whose real name is Karen Orzolek, announced Wednesday that she would release an LP titled Crush Songs, a collection of tunes recorded in 2006 and 2007.
"When I was 27, I crushed a lot. I wasn't sure I'd ever fall in love again. These songs were written and recorded in private around this time," she said in a release about the upcoming album. "They were the soundtrack to what was an ever continuing love crusade. I hope they keep you company on yours."
Karen O also shared the album cover art, which features her own drawings, on Twitter.