Osbourne, 22, will join the cast at London's Cambridge Theater, playing the role of prison matron Mama Morton during a seven-week run starting Sept. 10, the theater said Monday.
She found fame on the reality show "The Osbournes" alongside her parents, Ozzy and Sharon Osbourne, and her brother, Jack. She has recorded several albums, and was host of the British TV show "Project Catwalk."
Meanwhile, Ozzy Osbourne was doing well after undergoing a "minor outpatient procedure" late Saturday at Rose Medical Center in Denver, his representatives said. He was released early Sunday.
KUSA-TV in Denver reported the 58-year-old rocker underwent surgery for a blood clot in his leg.
Leslie Horna, a spokeswoman for HealthONE, told The Associated Press she had no other information on the procedure.
Osbourne was in Denver to perform at Ozzfest.