My Best Friend's Wedding (1997)

Synopsis
A woman realizes that friends can be lovers, but now has to convince the friend in question in this romantic comedy. Michael O'Neal (Dermot Mulroney) and Julianne Potter (Julia Roberts) were romantically involved in college, and after breaking up, they have managed to remain close friends. For years, Julianne and Michael have had a pledge that if both were single when they turned 28, they would get married. Shortly before her 28th birthday, Julianne is lamenting the sad state of her love life when she gets a call from Michael, who announces that he has important news. Julianne is convinced that Michael is going to ask her to marry him, and she is crestfallen when he announces that he's engaged to Kimmy Wallace (Cameron Diaz). Kimmy seems like the perfect woman for Michael; she's sweet, pretty, bright, and adores Michael, and her wealthy family is just as fond of him as she is. But now that Julianne has realized how much she loves Michael, she's not about to give him up without a fight -- and isn't afraid to fight dirty. Julianne's uneasy ally in the battle for Michael's affections is her friend and editor George Downes (Rupert Everett), a cheerfully out-of-the-closet homosexual who is not prepared when Julianne asks him to pose as her boyfriend. ~ Mark Deming, All Movie Guide