Back in 2000, we were introduced to Vitamin C via the seemingly inescapable "Graduation (Friends Forever)".
You may also remember her singles "The Itch"...
...and, more notably, "Smile".
But back in 1988, she was an actress going by her government name, Colleen Fitzpatrick, and her first role was in none other than John Waters' Hairspray.
She went on to have roles in The Naked Gun 2½: The Smell of Fear, Liar Liar, and Dracula 2000 , and performed in a band called Eve's Plum before going solo in the early 2000s. As of 2012, she's the Vice President of Music at Nickelodeon, so it seems as if she's doing fairly well for herself.