Kelly made her professional acting debut in the fact-based made-for-TV movie "Love, Lies and Murder", playing teenager Cinnamon Brown, who was coerced by her father into killing his wife and her stepmother, Linda Brown. She was originally going to have a starring role as Polly Pry in Trey Parker and Matt Stone's "Cannibal! The Musical", but Kelly was convinced not to do so by her agent out of concerns it could potentially ruin her career, and was ultimately replaced with Toddy Walters, though she was still credited in the end credits under her initials "M.K." as "the Dropout". She went on to have small roles in the films "The Boy Who Cried Bitch", "Hi-Life", and "Billy Bathgate" before being cast as Donna Hayward in "". For that film, she went home and got permission from her priest because of an explicit sex scene. In the same year, she starred opposite D. B. Sweeney in the romantic comedy "The Cutting Edge" and played two roles opposite Robert Downey, Jr. in "Chaplin". According to a "TV Guide" interview, before taking on her role in "Daybreak", Kelly once again asked her priest for advice: "Being a Catholic, I wondered if it would be against my religion to play a girl who has premarital sex." The priest told her "it was okay, as long as my artistic intentions were true and I wasn't doing it for the notoriety or the money."