Shes All That (1999)

High school hotshot Zach Siler (Freddie Prinze Jr.) is the envy of his peers. But his popularity declines sharply when his cheerleader girlfriend, Taylor (Jodi Lyn O'Keefe), leaves him for sleazy reality-television star Brock Hudson (Matthew Lillard). Desperate to revive his fading reputation, Siler agrees to a seemingly impossible challenge. He has six weeks to gain the trust of nerdy outcast Laney Boggs (Rachael Leigh Cook) -- and help her to become the school's next prom queen.