The actress, who got married to Pitt this August, shared her friends' warning while talking to Today Show's host Richard Wilkins Friday, reports dailymail.co.uk.
Jolie, who is directing the film as well, and Pitt play a husband and wife struggling in their relationship in "By The Sea", which will release in 2015.
"We haven't acted together for ten years. We decided we would do it again and we did a very small drama about family, about marriage in fact. We did a drama about a bad marriage," she said.
"A lot of friends of ours thought it was a really... they didn't say a bad idea... but they asked us a few times if we were sure we wanted to do it," the actress added.
The couple last starred opposite each other as assassins in "Mr. And Mrs. Smith", which was released in 2005.
The comment comes after the couple was spotted engaged in a tense exchange on the balcony of their Sydney hotel room last week.
