The actress, who raises six children with Pitt, will star and direct the film. It is their first onscreen reunion after 2005 'Mr & Mrs Smith'.
"We are working together on a drama about grief and finding a way through a difficult marriage," Jolie, 39, told People magazine.
"We find it very funny that it's our honeymoon," the actress said.
Pitt-Jolie costar as a married couple who become obsessed with their neighbors in the film, which was written by Jolie.
The film costars French actress Melanie Laurent, who also appeared with Pitt in 2009's 'Inglourious Basterds'.