Colleen Ann Fitzpatrick (born July 20, 1970 in Old Bridge, New Jersey) is an American pop music artist, dancer and actress, better known by her stage name, Vitamin C. Her hits include "Smile", "As Long As You're Loving Me", "Graduation (Friends Forever)" (which reached #38 on the Billboard Hot 100), "The Itch" and "Vacation" (from the Pokémon Pikachu's Vacation soundtrack).

Before going solo, Fitzpatrick was the lead singer of punk pop band Eve's Plum. She is currently recording her third album.

Colleen had made her first foray into acting in John Waters' 1988 feature film Hairspray as the bratgirl Amber von Tussle, and later appeared in Dracula 2000 (2000), as Lucy Westerman, and Rock Star (2001). She made a brief comedic cameo as herself (in voiceover) in the film Scary Movie 2. She was also a judge in the American Idol spoof television show The WB's Superstar USA. Also in 2002, she appeared in a celebrity game show called Celebrity Bootcamp alongside ex gangster-rapper Coolio, but was kicked out in the first episode along with Nikki Zeiring. She made short cameos on Sabrina, the Teenage Witch, Brothers Garcia, The Amanda Show and The Sausage Factory.