Jennifer Aniston and Brad Pitt could have starred in the movie Titanic

 Kate Winslet and Leonardo DiCaprio acted in Titanic, Kate as Rose and Leonardo as Jack.

There were other A-list actors were considered for the leading roles such as Jennifer Aniston, Brad Pitt, Angelina Jolie, Johnny Depp, Winona Ryder etc.

But Winslet determined to grab the role of Rose and called Titanic's director, James Cameron to give her the role. 

DiCaprio initially didn't want to take the role because he was looking for different characters, instead of heartthrob.

Winslet went to convince DiCaprio and finally he took the role.