She's All That(1999)

High school hotshot Zach Siler is the envy of his peers. But his popularity declines sharply when his cheerleader girlfriend, Taylor, leaves him for sleazy reality-television star Brock Hudson. 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 -- and help her to become the school's next prom queen.