Mendelsohn's latest film, Rogue One: A Star Wars Story, premiered earlier this month. Forrest, a writer, did not join the actor at the movie's premieres throughout the last few weeks. The couple was last seen at a public event together at Vanity Fair's 2016 Oscars after-party in February.
According to court documents obtained by ET, Forrest lists the date of separation as Dec. 1, 2016, and is asking for joint legal custody and primary physical custody of their 3-year-old daughter, Carolina, with visitation for Mendelsohn.
Forrest is also asking the court for spousal support, and asks for attorney's fees to be paid by the actor. Communal assets will be divided at a later date. Mendelsohn has 30 days from the date of Forrest's filing to issue a response.