My Best Friend's Wedding (1997) plot summary

Julianne (Roberts) and Mike (Mulroney) are best friends after a failed romance. After a few months apart, Mike phones Jules to tell her that he is marrying Kimberley Wallace (Diaz), daughter of wealthy Red Sox owner Walter Wallace. Mike tells Jules that he needs her so she flies to Chicago. She hopes to finally say goodbye to the man of her dreams, but she ends up falling in love with him again just as he is planning to marry Kim. Jules hatches a secret plan to get Mike fired form his dream job and pretend Kim's father wanted him fired so Mike would have to work for him and Kim would be able to study. Mike gets fired and decides to call it quits with Kim. Jules sees her opportunity, but feels horrible about betraying her best friend. Jules confesses her feelings to Mike on the day of his wedding. She kisses him and Kim sees. Jules realizes Mike is not in love with her and she goes to find Kim before it is too late.