Mr. and Mrs. Smith: The movie that famously brought Brad Pitt and Angelina Jolie together also famously destroyed the actor's marriage.
Days of Thunder: Tom Cruise was married to Mimi Rogers when he met his co-star Nicole Kidman.
Proof of Life: Reportedly, Meg Ryan and Dennis Quaid’s marriage was already on the rocks before this movie was shot, with Quaid allegedly cheating on Ryan.
Daredevil: Jennifer Garner was married to Ben Foley and Ben Affleck was engaged to Jennifer Lopez, when the two started shooting 'Daredevil' (2003).
The Outlaw Josey Wales: Clint Eastwood was married to Maggie Johnson at the time, but fell in love with his co-star Sondra Locke.
Mary Shelley’s Frankenstein: Kenneth Branagh was married to Emma Thompson when he fell for his co-star Helena Bonham Carter.
The Misfits; The script of 'The Misfits' (1961) was based on a story by playwright Arthur Miller, who was married to Marilyn Monroe at the time
To Have and To Have Not: Hollywood heartthrob Humphrey Bogart was married to fellow actress Mayo Methot at the time.
Cleopatra: Cleopatra' (1963) brought together two famous Hollywood stars: Elizabeth Taylor and Richard Burton.
Titanic: Director James Cameron was married to Linda Hamilton when he started working with actress Suzy Amis (who played Rose's granddaughter).