"It's time to move on," Sharon recently told The Post.
Osbourne's decision was reportedly in response to NBC's alleged move to drop her son Jack Osbourne from the cast of the network's upcoming reality show Stars Earn Stripes -- which will feature celebrities competing against one another in tough military-style challenges -- shortly after he disclosed he suffers from multiple sclerosis.
"I just can't be fake. It's discrimination, and it was badly handled," said Sharon, who had reportedly been in heated arguments with NBC after Jack was released from Stars Earn Stripes via email just two days before the show began production in June.
Sharon, who is still under contract to continue judging America's Got Talent's current season, is reportedly furious with NBC because they also allegedly lied to the media about how the situation went down.
"They can't make me do something I don't want to do," she told The Post. "All they can do is stop me from being a judge on another network for five years."
Jack first claimed he was fired from Stars Earn Stripes due to his medical condition in June. However, producer David Hurwitz reportedly insisted last month at a Los Angeles press conference that the network was just in talks with the celebrity and never officially signed him on to be a competitor.
Both Jack and Sharon aren't denying that Jack never formally inked a 50-page contract that parties had been negotiating, but according to The Post, the Osbournes firmly believed a verbal agreement and commitment should've been sufficient at the time considering Jack's Stars Earn Stripes participation had been discussed in good faith.
"I was working without a signed contract right up until the live shows started on America's Got Talent," Sharon explained. "Everything is done at the last minute. We took six months to negotiate back and forth."
Jack reportedly received an email from NBC in May confirming he'd appear on Stars Earn Stripes. One month later, Jack revealed he had multiple sclerosis and then shortly afterwards received a follow-up email "regretfully" declining his participation.
Sharon is claiming NBC offered to pay Jack the full salary he would've received from competing on the show, but he didn't want nor care about the money.
"He wanted his gig. It gave him something to look forward to when he was diagnosed," Sharon told The Post. "Think of the good that it could have done to show other people who have this [condition] that your life is not over."