Leighton Meester and Gillian Jacobs have begun filming The Life Partner, Digital Spy said.

The comedy was one of 12 feature film projects selected for the Sundance Institute Screenwriters Lab in 2012, and also stars Adam Brody, Gabourey Sidibe and Kate McKinnon.

Jacobs plays a young woman who drunkenly promises her lesbian best friend (Meester) that she won't get married until gay marriage is legal.

But when her boyfriend (Brody) proposes, things become more complicated.

The film has been largely unpublicised, but according to the Facebook page of actress Simone Bailly, filming is now underway in LA.

Originally a play, the script was co-written by director Susanna Fogel and Joni Lefkowitz.

Meester was recently cast alongside Robert Downey Jr and Vera Farmiga in drama The Judge.