Osbourne's fiancee wants NBC boycott NBC responds to Osbourne allegations The real reason Osbourne quit   Play video

Sharon Osbourne has opened up about her decision to quit America's Got Talent, insisting a dispute with TV chiefs over her son Jack's multiple sclerosis diagnosis prompted her resignation.

The British TV personality took to Twitter.com on July 24 to respond to remarks made by fellow judge Howard Stern about her departure - but did not expand on her reasons for quitting the show on U.S. network NBC.

She wrote, "My darling Howard Stern, money is not the reason I'm not returning to (America's Got Talent), it's because..."

Osbourne has now revealed she felt compelled to quit after her son Jack was allegedly dropped from new show Stars Earn Stripes, which pits celebrities against one another in military training exercises, after he went public with his health battle in June.

She tells the New York Post, "I just can't be fake. It's discrimination, and it was badly handled.

"It's time to move on. All they can do is stop me from being a judge on another network for five years."

Producer David Hurwitz told a press conference in Los Angeles last month that Jack was never officially hired, but Sharon and her son allege they were moving forward with the TV show plans on a verbal commitment.

A representative for the network says, "Sharon has been a valuable part of the NBC family. We regret any misunderstanding and wish Jack well."

Osbourne, who is also a co-host on U.S. daytime chat show The Talk, has been a judge on America's Got Talent since 2007.