The Rock is Dead star had to pretend to eat the slimy worm, but he was told he couldn't bite down or swallow the creature.

"I was a little disappointed that the leech handler wouldn't let me be a little bit rougher with them," he says. "They don't really have nervous systems, technically. But I remember as a little kid I used to pour salt on slugs. They're probably from the same family. And I have eaten escargot (snails) before, so I figured, 'Why not eat the leech? It's not that big of a deal'.

"I wasn't technically allowed to swallow it."

The singer appears in the third season of the show, which premieres in America on Wednesday (02Nov16).