Sharon Osbourne is so scared of her daredevil son Jack being kidnapped by gangsters in South America, she's banned him from visiting the continent.

The 19-year-old takes on a number of dangerous challenges for his new TV show Jack Osbourne: Adrenaline Junkie, including mountain climbing, martial arts and running with the bulls in Pamplona, Spain.

But Sharon was so scared about his safety, she banned him from putting himself at too much risk.

He says, "She's had her say about the show quite a bit, 'No skydiving, no bungee-jumping and no going to South America.'

"If a gangster catches on that Jack Osbourne is in South America, he knows he can kidnap me, cut off my ear, send it to my mum and ransom me for a few million."