Jack Osbourne has been diagnosed with multiple sclerosis.
The 26-year-old - who has recently become a father - was found to have the incurable autoimmune disease after a frightening spell in which he lost 60% 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.
He has spoken out to raise awareness of the condition and the support of his fiance Lisa Stelly - who gave birth to baby Pearl two months ago - is helping him to keep a positive outlook.
Jack went for tests at the same hospital his daughter Pearl had been born just three weeks earlier. The condition affects the brain and the nervous system.
Jack Osbourne can be role model for multiple sclerosis sufferers, MS survivor and advocate Nancy Davis told Daybreak this morning.
Black Sabbath star Ozzy and former X Factor judge Sharon have also been stunned and are still struggling to come to terms with their son's condition, which was confirmed by a neurologist last month.
Jack - an extreme sports enthusiast - will use a combination of daily drug treatments, holistic therapies and lifestyle changes.