Ashton Kutcher stunned Two And A Half Men co-star Jon Cryer and their crew members shortly after landing his role on the sitcom by offering to wear a prosthetic penis he conveniently had in his trailer for a nude scene.

Kutcher had only just replaced fired Charlie Sheen on the show when he had to reveal himself during an episode, and it was at that point that Cryer knew he had the perfect castmate.

Looking back at their time together on the show, which ends in the U.S. on Thursday night (19Feb15), Cryer recalls the moment he knew that himself and Kutcher would be great co-stars.

The Pretty in Pink star tells U.S. chat show host Conan O'Brien, "There was a point at which he was supposed to drop trou (trousers) and be completely naked in front of me and we didn't know how to do that in front of a live studio audience without him actually being naked...

"Then Ashton pipes in, 'Oh, well I've got a huge prosthetic penis in my trailer...' We all had that awkward moment of, 'Of course you do...' It was a flesh-coloured (mid-section) with a very impressive anatomically-correct member... That's how I knew he belonged on the show."

Kutcher had the prosthetic created for a practical joke show, in which a character named Naked Man would literally hang out at hotspots all over Los Angeles, and kept it.

He adds, "It had its own case... My housekeeper found it one day and I was single one day. She had all kinds of ideas."