The movie is a Nu Image/Millennium Films production that Lionsgate will distribute in the United States and the United Kingdom.
Details of the project were announced Wednesday by Joe Drake, president of Lionsgate's motion picture group; Jason Constantine, Lionsgate's president of acquisitions and co-productions; and Avi Lerner, founder and co-chairman of Nu Image, which is handling international sales of the film.
Written and directed by Justin Zackham, the film will co-star Katherine Heigl, Amanda Seyfried, Robin Williams, Ben Barnes and Topher Grace.
The movie is about a long divorced couple, played by De Niro and Keaton, forced to pretend at their son's wedding that they are still happily married, Lionsgate said in a synopsis.
"'The Big Wedding' is a charming, rollicking movie that promises to be an instant inter-generational family comedy classic," Drake said in a statement.
"We are thrilled to be in business once again with Avi and Nu Image," added Constantine. "After our success together with action genre films like 'The Expendables' and the upcoming 'Conan the Barbarian,' this film presented a wonderful opportunity to expand our collaborative horizons into the realm of broad comedy."