Jack Osbourne has had symptoms of multiple sclerosis for "three or four years"
The 26-year-old star was diagnosed with the autoimmune disease - which affects the central nervous system - five weeks ago after suffering vision loss in his right eye but has now realised he was showing signs of the condition for some time prior to his doctor`s assessment.
He said: "I guess I`ve been having symptoms for the last three or four years, but I didn`t realise it.
"I had problems with my bladder, problems with my stomach and then, about two years ago, my legs went numb for two months and I just thought I had pinched a nerve."
Despite suffering from vision loss, Jack - who was diagnosed just two weeks after his fiancee Lisa Stelly gave birth to their daughter Pearl - says he has now regained "about 80 per cent" of his sight back, though he doesn`t know whether it will completely return.
He said: "They don`t know if it will ever improve beyond that, but everyone`s different.
"[My vision] will return to some capacity but like I said, everyone is different, some people are left with a blind spot, some people return a 100 per cent, some people never even get anything back, so it`s hit or miss."
The `Adrenalin Junkie` host insists he is currently feeling good but knows the nature of his condition means that could change at any time.
Speaking on `The Talk` - on which his mother Sharon Osbourne is one of the presenters - he said: "Honestly, I`m fine. [But] one minute you can be fine and the next, I went blind in my right eye. It`s a completely unpredictable disease."
And Jack admits becoming a father has meant he doesn`t have time to dwell on his illness.
He said: "It`s been good because I haven`t had time to be like, `Oh, I have MS,` because I have to change diapers and stop the baby from crying."