Revered actor Kenneth stepped behind the camera to helm the action fantasy movie and he cast the young Australian in the lead role.

He admits he was reluctant to encourage the actor to take off his shirt for a scene, but vowed to push for the saucy moment after his wife urged him to get Chris to strip.

And when Kenneth finally plucked up the courage to mention the idea, Chris was delighted - because he had been working hard in the gym for months to get in shape for the demanding role.

"I was a bit embarrassed when we came to do the scene in the movie when he takes his shirt off," Kenneth confessed to U.K. talk show host Graham Norton.

"I felt uncomfortable talking about how we would do it and how he might feel he shouldn't. I even rang my wife to ask her and she said rather over enthusiastically, 'Get him to take his shirt off!'

"When I broached it with Chris he said, "Of course I'm going to get my b**ody shirt off mate. I've been training for nine months for this thing!"

After the cameras stopped rolling on the 2011 movie, it was clear Kenneth and his lead man had got on famously on-set - Chris later told of his disappointment that the veteran stage star would not be directing the sequel in 2013.

Chris said at the time, "I'm really disappointed. Ken built that character, and everything I know about the Thor world I learned while shoulder-to-shoulder with Ken. I learned so much from him.

"As long as he's happy, that's the thing. I learned so much from Ken while we built (the first film), so at least I had that time with someone like that. The start of anything creative is the most important period in a way. That's when the most can go wrong, and Ken made sure we got it right."