Ozzy Osbourne didn't believe his son Jack's MS diagnosis at first, because he'd been misdiagnosed himself in the 90s.
Jack, 33, was diagnosed with multiple sclerosis - a disease which targets the nerve cells in the brain and spine, and disrupts the functionality of the nervous system - seven years ago when he was 26, and has said in a new interview that his father and Black Sabbath rocker Ozzy was skeptical of the result because he was once misdiagnosed with the condition and doesn't understand how medicine has evolved.
He said: "My dad was very much of the mindset of like, 'No, that's wrong.' His inkling is, it's still the 1990s and they're still not good at diagnosing it."
The TV star - who has three daughters, Andy, three, Pearl, six, and Minnie, 13 months, with his ex-wife Lisa Stelly - also admitted his mother Sharon Osbourne didn't take too well to the news either.
Speaking to Yahoo Lifestyle, he added: "My mom does not deal with bad news very well."
Since his diagnoses in 2012, the 'Ozzy and Jack's World Detour' star has set up a website called 'You Don't Know Jack About MS', in which he aims to give people "a better understanding" about the disease.
He said of the site: The whole point of 'You Don't Know Jack About MS' was to create a destination website for people to go and just learn the broad strokes about MS. What is it, how does it affect people, and cut through a lot of the noise that the internet tends to be full of. Here's the facts, it's easy to digest.
"But I don't want the focus to be on me. I know it's called that, and I'm hosting it, but I want the focus to be about the disease and kind of giving people a little bit of hope, and a better understanding about what it is."
Jack is still undergoing treatment for the condition, but said in 2016 he was "doing really well".
He said: "I'm doing really well right now, which is awesome, always good news. That's all I can really ask for at the moment. I'm feeling good, I'm taking care of myself, I'm sticking to my treatment plan, so things are good."