Sharon in tears about Jack's MS

Sharon Osbourne has broken down in tears on live TV while talking about son Jack's multiple sclerosis.

The reality star brought up Jack's recent diagnosis on her US chat show The Talk, saying: "It's been amazing for Jack because I really believe that... prayer really helps."

Sharon said she was devastated for her son, who has just welcomed daughter Clementine Pearl with fiancee Lisa Stelly.

She said: "And what I'm doing right now is not helping because I'm just feeling sorry for myself, and that is no good."

Adrenaline Junkie star Jack, 26, was found to have the incurable autoimmune disease after a frightening spell in which he lost 60 per cent of the vision in his right eye.

He and his family have revealed his condition in an interview with Hello! magazine in which Jack said he had experienced a range of emotions.

"While I was waiting for the final results, I got really, really angry," he said.

"Then I got really sad for about two days, and after that I realised, being angry and upset is not going to do anything at this point - if anything it's only going to make it worse. 'Adapt and overcome' is my new motto."