Jack Osbourne thinks his father Ozzy will live until he is 900.

The 25-year-old star says his rocker dad is surprisingly healthy considering his rock 'n' roll lifestyle and he jokes he will be outlived by his famous parent.

He said: "He's great. He always has physicals and last time the doctor said he was as fit as a 30 year old – that's pretty good going for a 62-year-old man who's had a wild life. He's happy about that.

"Motorbikes can't kill him, drugs can't kill him. He's one of those guys who will live to like, 900 years old, and still be complaining about everything and laughing. We joke that he's going to outlive me."

Jack recently made a documentary about his father but didn't spend too much time with his dad during filming as he didn't want to ruin their relationship.

He explained to Britain's Star magazine: "I didn't actually spend that much one-on-one time with my dad. My new documentary is one thing but sacrificing our relationship for the sake of entertainment is not something I'm into any more.

"We gave up so much doing 'The Osbournes' with certain moments between me and my dad."