On Tuesday, his mother Sharon Osbourne opened up to her co-hosts on "The Talk," thanking fans through tears for their support.
"He's great, he's doing really really good," she said. "I want to thank everyone for your goodwill and messages."
"It's been amazing for Jack, because I really believe that vibes and prayer help. And what I'm doing right now is not helping, because I'm just feeling sorry for myself, and that is no good. So we have to think positively and get on with this show that we love."
Jack Osbourne, whose dad is Black Sabbath rocker Ozzy Osbourne, became a dad himself in April when he and his fiancee, actress Lisa Stelly, welcomed daughter Pearl Clementine. Ozzy told Hello! Magazine that he had doubts about Jack's diagnosis because Ozzy himself had been diagnosed with M.S. a few years ago--only to find out the doctors' first tests were wrong.
"I want Jack to go for a second opinion as I was diagnosed with M.S. a few years ago. It took them six months to work out that I have a rare hereditary tremor called Parkin Syndrome."