When most people hear the name Adrian Grenier, they think of his role as Vincent Chase on the HBO series 'Entourage.' Since he started hanging with E, Drama and Turtle back in 2004, Grenier's career has taken off, leading to numerous awards and roles in movies like 'The Devil Wears Prada' opposite Anne Hathaway.

However, did you know that before he firmly cemented his place in Hollywood, Grenier starred in a Britney Spears music video? Specifically, her clip for '(You Drive Me) Crazy,' the title track for 1999's 'Drive Me Crazy' starring Grenier and Melissa Joan Hart -- not his best cinematic moment, folks.