My Best Friend's Wedding (1997)
Michael O'Neal (Dermot Mulroney) and Julianne Potter (Julia Roberts) have been friends for years but when Michael rings Julianne to tell her he is getting married to a lady called Kimberly Wallace (Cameron Diaz) she finally realises he has to him her true feelings, which are that she loves him. When she gets there she can't do it so she tries to do everything to get them to break up.