Simon Cowell walks off stage during interactive ventriloquist act in Britain's Got Talent semi-final

The performer asked Cowell and fellow judge David Walliams to parttake in his show, and proceeded to get them on stage wearing masks, turning Cowell into a dummy and Walliams into a faux ventriloquist (Tamley did both voices, as the mechanical mouths on the masks moved along in sync).

Cowell was clearly displeased, as the singer made jokes directed at the pair, and asked the BGT stalwart to do the can-can.

And he was fed up by the time Tamley tried to get the two of them into a wooden box to close out his performance - at which point he removed his mask and attempted to walk off. But Tamley managed to get him back on stage, and strapped the mask back on to his face, ending his act as he had intended. It made for pretty awkward TV.

Check out a clip of the performance below.

Viewers were split over Cowell's reaction, with some feeling that he should have played along for the sake of Tamley's act.

"Simon Cowell needs to get over himself just a bit!" Tracey Davies tweeted. "What a bad sport - felt quite bad for the guy."

Other viewers, however, felt that Cowell was put in an awkward position, and was within his rights to try and escape the situation.

"Can people stop having a go at Simon Cowell for walking off stage," Sarah Caldwell tweeted, "it was evident it was completely out of his comfort zone and he couldn't cope with it. Not spoilt, not an idiot, just human."

David Steedman concurred. "Sorry, but if you don't like something, you don't have to do it," he wrote. "I say fair play to Simon Cowell for doing exactly what he wants to do."