Sharon Osbourne has left "America's Got Talent" saying she "just can't be fake" after her son Jack was "fired" by NBC.

Osbourne, 59, had been one of the reality talent show's judges for seven seasons. She told the New York Post that she could not stay after NBC "fired" her son Jack from Stars Earn Stripes, a new reality series.

Jack, 26, had been diagnosed with multiple sclerosis earlier this summer.

"I just can't be fake," Osbourne told the Post, adding, "It's discrimination, and it was badly handled."

Osbourne said she fought bitterly with NBC executives over the matter, noting the network fired Jack via email just two days before the show's production began.

She's willing to pay the penalty for departing the series early, too; she remains under contract with NBC.

"All they can do is stop me from being a judge on another network for five years."

For its part, NBC has denied ever firing Jack Osbourne.

"He was somebody we were in talks with," producer David Hurwitz said, noting Jack had not signed contracts in relation to the new show.

NBC Entertainment Chairman Bob Greenblatt released a statement Monday, saying NBC "does not discriminate on any basis."

Greenblatt refused to discuss Jack's medical condition. But he explained "Stars Earns Stripes" requires "dangerous water stunts, strenuous physical activity, and uses live ammunition."

Greenblatt pointed out the network offered Jack Osbourne two alternative roles on the show but he declined both.

"We have the deepest affection for Sharon Osbourne and consider her to be part of the NBC family," Greenblatt said in a statement. "Our hearts go out to her, Ozzy, Jack and his family at this time."

'Stars' is set to debut on Aug. 13.

"Sharon has been a valuable part of the NBC family. We regret any misunderstanding and wish Jack well," an NBC rep told the Post Sunday.