She'll play the matriarch of a blended family of 12 - a role that has previously been played onscreen by Bonnie Hunt and Myrna Loy.
The film, based on a real family, first hit the screen in 1950 with Loy and Clifton Webb. A 2003 remake, starring Steve Martin and Hunt, spawned a 2005 sequel.
The new version will debut on the Disney+ streaming site in 2022.
Gabrielle Union was last seen on the big screen in 2018 with drama "The Public" and action thriller "Breaking In". On TV, she's one of the regulars on "L.A.'s Finest", a spinoff of the "Bad Boys" franchise.
The actress also served as a judge on "America's Got Talent" last year. Her contract was not renewed after one season and it ended with a fallout as she accused the producers of racism, which led to an inquiry by NBC.
She then filed a harassment complaint against the Peacock, claiming the network's entertainment chief, Paul Telegdy, tried to silence her reports of racism. She called the company "a snake pit of racial offences" and alleged that representatives for the organisation had threatened her agent.
After months of drama, both parties eventually reached an "amicable resolution" in September this year. Details of the deal were not disclosed but the star reportedly received "significant" compensation.