Jack Osbourne's fiancee calls for NBC boycott

Jack Osbourne's fiancee is demanding fans boycott U.S. network NBC amid allegations the reality TV star was dropped from a new strength-training show following his recent multiple sclerosis diagnosis.

Jack's mum Sharon Osbourne sparked the controversy after announcing she was quitting her role as a judge on another NBC programme, America's Got Talent, at the end of the current season.

She claimed she felt compelled to resign when she learned Jack had reportedly been dropped from the line-up for Stars Earn Stripes, in which celebrities battle it out in military training sessions, after going public with his heartbreaking health news in June .

NBC bosses responded to the accusations on Monday, insisting Jack was never asked to compete on the show, although he was offered other jobs on the series, which he turned down.

A statement read: "We hold medical information in strict confidence and therefore cannot comment specifically about Jack, but as a company that cares deeply about the health and safety of everyone on our shows - especially one like Stars Earn Stripes - that requires dangerous water stunts, strenuous physical activity, and uses live ammunition - we required all potential participants to undergo medical vetting to ensure that they could safely participate... This network does not discriminate on any basis."

However, Jack has taken offence to the suggestion that his multiple sclerosis would hamper his ability to perform, and he took to his Twitter.com blog on Tuesday to fire back at the network.

He fumed, "I took part in a 16 hr (hour) challenge over 30 miles with a 40lbs (pound) ruck (sack) on my back in Jan (January). I had MS then. Don't tell me wot (sic) physically demanding is".

And his fiancee Lisa Stelly wants fans to turn their backs on NBC, just like her future mother-in-law has.

Commenting on the NBC statement, she tweets, "Liars! bull-f**king-s**t. boycott NBC".