The Hot Chick(2002)

Jessica Spencer, a somewhat mean-spirited teen, is convinced that she has the perfect life. She's the hottest, most popular girl in high school, captain of the cheerleading squad and dating the dreamy quarterback. But she gets a big dose of reality when--due to a spell--she wakes up in the body of a thirty-year-old man. She quickly discovers that trading on your looks isn't so easy when you're a girl who constantly needs a shave. Moreover, until she can figure out how to change herself back, Jessica must find a way to win the "Cheer Competition," go to the prom, and get her boyfriend back--all while she's still a guy. In the process, she learns how shallow her life has been.