Today is Julianne Hough's birthday! The multi-talented actress may have gotten your attention on Dancing with the Stars, but she was totally a part of your childhood — and you had no clue. Did you know that the dancer was an extra in Harry Potter and the Sorcerer's Stone way back in 2001? It's absolutely mind-blowing to see her in Hogwarts garb.
Click through to see more stars you didn't know were in Harry Potter movies, and let us know which one shocked you the most in the comments!