Lionsgate has released the first trailer and the second poster for The Big Wedding, writer-director Justin Zackham's ensemble family comedy arriving in theaters this fall. Robert De Niro and Diane Keaton star as a bitter, long-divorced couple who are forced to play nice for their adopted son's wedding. Take a look at the first footage from this romantic comedy, along with the new 1-sheet.

The Big Wedding Poster

With an all-star cast lead by Diane Keaton, Robert De Niro, Susan Sarandon, Robin Williams, Katherine Heigl, Amanda Seyfried and Topher Grace, The Big Wedding is an uproarious romantic comedy about a charmingly modern family trying to survive a weekend wedding celebration that has the potential to become a full blown family fiasco. To the amusement of their adult children and friends, long divorced couple Don and Ellie Griffin (Robert De Niro and Diane Keaton) are once again forced to play the happy couple for the sake of their adopted son's wedding after his ultra conservative biological mother unexpectedly decides to fly halfway across the world to attend. With all of the wedding guests looking on, the Griffins are hilariously forced to confront their past, present and future - and hopefully avoid killing each other in the process.