Sharon Osbourne says she's quitting "America's Got Talent" because the network fired her son Jack from a new military-themed reality show after he disclosed that he has multiple sclerosis, the New York Post reports.

According to Osbourne, Jack was fired from "Stars Earn Stripe"s by e-mail in June, two days before he was supposed to report to work and shortly after he publicly disclosed his MS diagnosis. But the show's producer, David Hurwitz, said at a news conference last month that, while the network had been "in talks" with Jack regarding the show since April, he had never officially been hired.

According to the Post, all parties agree that the contract NBC sent to Jack was never signed. But Jack and Sharon Osbourne insist they were operating on good faith that Jack would be participating on the show - based in part on Sharon's own experience with "America's Got Talent" ("I was working without a signed contract right up until the live shows started," Sharon says.