Ewan McGregor left red-faced during sex scene with Christian Bale

Ewan McGregor has revealed that he was left embarrassed while filming a sex scene with Christian Bale as they did not realise the crew had quit filming them while they were in action.

McGregor, 40, who plays a rock star in the 1998 drama ‘Velvet Goldmine’, admitted that their romp on a rooftop in London was an awkward moment in his career.

"I did have a sex scene with Christian Bale, which I did to the best of my ability. I was playing an Iggy Pop-type rock star and we have a s**g on top of a rooftop but they wanted to shoot it from another rooftop," the Daily Express quoted him as telling talk show host Graham Norton.

"We heard, 'Action!' so we started to slowly (simulate sex). Then it went on and on. Then I thought, I would have (finished) by now so I went round to his ear and went, 'I think I would have (finished) by now. I'm going to have a look.' I looked over and they were packing up the cameras!

"They must have said 'cut' really quietly. I think they thought it was a sensitive thing, they should just leave it to us. There's nothing wrong with (screaming), Cut!" he added.