* Robert De Niro and Al Pacino: The two actors have been rivals for decades, and they have often traded barbs in the press.
* George Clooney and Russell Crowe: The two actors had a falling out while working on the movie "Syriana", and they have not spoken to each other since.
* Brad Pitt and Angelina Jolie: The two actors were once Hollywood's golden couple, but their relationship ended in a bitter divorce.
* Tom Cruise and Katie Holmes: The two actors had a whirlwind romance and marriage, but their relationship ended in a messy divorce.