Sharon Osbourne has quit 'America's Got Talent' because of the network channel NBC's “discrimination” against her son, Jack Osbourne.

The showbiz mum was furious when 26-year-old Jack was fired by email from reality television show, 'Stars Earn Stripes', allegedly because of his multiple sclerosis (MS) diagnosis. She has now decided she no longer wants to work for the television network.

Sharon told the New York Post newspaper she just cannot be fake.

“I just can't be fake. It's discrimination and it was badly handled. It's time to move on.”

The wife of Ozzy Osbourne remains under contract to NBC but said she isn't worried about any consequences.

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

Last month, however, 'Stars Earn Stripes' producer David Hurwitz said Jack was never actually hired for the tough reality contest.

Jack, who was first contacted about the show in April, before his diagnosis, admits a contract was never signed but insists the deal was moving forward on a solely verbal commitment.

Jack went public with his medical condition in June. He received an email on May 8^th from NBC confirming his participation. However, not long after announcing his condition, Sharon said he received an email from NBC, which read, “We cannot move forward with Jack's participation.”

Sharon also claims NBC offered to pay Jack a full appearance fee.

A NBC representative said they regretted any 'misunderstanding' which has led to Sharon leaving 'America's Got Talent'.