ABC will present the television special, although no air date has been announced.
Hibbert has starred on Broadway in Noises Off, The Green Bird and Me and My Girl. He won an Obie for his performance in Jeffrey.
Robert Weil played the Wizard in the original 1959 production of Mattress.
Ullman, the comedic actress best known for her Fox series "The Tracey Ullman Show," will play Princess Winnifred opposite the original Princess, Carol Burnett. Burnett starred in Mattress on Broadway in 1959 and on television in 1964 (in black and white) and in 1972 (in color).
Wicked's Marc Platt has joined the production as an executive producer. Burnett and Marty Tudor are also executive producers of "Mattress," which will begin filming Sept. 7 in Vancouver under the direction of Tony Award winner Kathleen Marshall.
Once Upon a Mattress, which is essentially the fable of "The Princess and the Pea" set to music, marked Burnett's Broadway debut, and her role as the comical Winnifred became one of Burnett's signature parts. Featuring a score by Mary Rodgers (music) and Marshall Barer (lyrics) and a book by Barer, Jay Thompson and Dean Fuller, the original Broadway company also included Jack Gilford, Joe Bova and Jane White. The 1996 Broadway revival featured "Sex and the City" star Sarah Jessica Parker in the role created by Burnett with co-stars David Aaron Baker, Jane Krakowski and Mary Lou Rosato.