Help with Movie Title

I am trying to remember the name of a movie that I used to love watching as a kid. In the movie, a popular girl disguises herself as a boy for a newspaper article. She goes to a new school and ends up becoming friends with a guy. She tries to help the guy by giving him a makeover so that he can get the popular girl. As this all happens she falls for him. At the end of the movie, they all go to prom and somehow her shirt is ripped open and she admits she's a female. I believe the movie was made in the 80's. Please help...this is driving me crazy!