Jack Osbourne has been diagnosed with multiple sclerosis.

The 26-year-old TV star - the son of Sharon and Ozzy Osbourne - and his fiancee Lisa Stelly welcomed their first child, Pearl, in April and Jack revealed getting the diagnosis two weeks after her birth left him devastated.

He told Britain's HELLO! magazine: ''While I was waiting for the final results, I got really, really angry.

''The timing was so bad. I'd just had a baby, work was going great - I kept thinking, 'Why now?'

''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.''

Jack discovered his condition when he lost 60 per cent of the sight in his right eye.

MS is an autoimmune disease which affects the central nervous system through the brain and spinal cord and people with the illness show symptoms with a change in their balance, vision and thought processes.

Jack's parents Sharon and Ozzy are struggling to come to terms with the diagnosis, with Sharon blaming herself for the devastating news.

She said: ''I keep thinking, 'What did I do wrong? What did I eat or drink when I was pregnant?' I feel like it's somehow my fault.''

Ozzy added: ''If it was me, you'd think, 'Ozzy had a reputation and it caught up with him,' but Jack is such a good guy.''

Jack's sister Kelly took to twitter to ask her fans to pray for her brother.

She wrote: ''Please support my brother @mrjacko in not only his bravery but honesty! i love you so much jack & I'm so proud of you! (sic)''

Jack wrote on twitter: ''Thank you all so much for the kind and inspirational words. It means a lot. #adaptandovercome (sic).''