Sharon Osbourne has slammed NBC for being ungracious.

The 59-year-old presenter - who quit her role on America's Got Talent because she claims the network fired her son Jack Osbourne via email from reality show Stars Earn Stripes following his diagnosis with multiple sclerosis (MS) - wants to be more selective about who she works with now she is getting older.

"I'm going to be 60 in October. So I'm at the age where I really want to work with people who I want to. And I felt that the network were not gracious. They handled the situation horribly. They've been backtracking, they've been not gracious with me at all," she said, explaining her decision to quit America's Got Talent.

Sharon admitted she is upset at leaving the show but she doesn't want to be a "hypocrite." Speaking on CBS This Morning, she said, "I love my principles and my son more [than America's Got Talent.] I would be a hypocrite if I went, 'Hi guys, how are you doing today?' I'm not that person. They don't like me, and I don't like them. They're stuck with me until next week. They don't want to be, believe me. But I'm going to turn up, and I'm going to do my final show and then I'm going to say 'bye.'"