Lavigne made Jenner her Sk8er Boi in May 2010, when they were spotted getting cozy in the club scene. It got so serious that he took her as his date to step-sister Kim Kardashian's wedding to Kris Humphries the next year. (As we learned from her nuptials with Kanye West, those plus-ones are super exclusive. Sorry, Kaitlynn!) Alas, neither relationship stood the test of time, and Jenner and the pop-punk singer broke up in January 2012.