The comedienne and the world champion poker player will compete to create a "pre-theater VIP party experience, sponsored by Kodak, for patrons attending Cirque du Soleil's hit show 'Wintuk,'" the network said in a news release.
The finale will be telecast live Sunday from the Museum of Natural History in New York City where last season's finalists -- winner Piers Morgan and runner-up Trace Adkins -- will make a special appearance before Donald Trump reveals the next "Celebrity Apprentice."
"This season's final boardroom showdown is guaranteed to be the most astonishing we've ever had, a fitting finale to a fantastic season," Trump, the show's star and executive producer, said in a statement. "Joan Rivers and Annie Duke have done a tremendous job. Congratulations to them both -- and may the best woman win!"
The finale will also feature the return of former "Apprentice" contenders Dennis Rodman, Tom Green, Melissa Rivers, Brande Roderick, Clint Black and Herschel Walker, NBC said.