Robbie Williams Trolls Dec Donnelly On 'Britain's Got Talent'

A classic move for the class clown at school was to stand behind the teacher and mimic everything that they did. It was easy, harmless, cheap humour that seemed to always get the laughs if it was done right.

Well, Robbie Williams is here to show you that it can still get a reaction even in adulthood.

Dec Donnelly was doing a bang up job presenting the latest episode of Britain's Got Talent until he realised that there was someone behind him mocking him.

As he was getting the crowd excited for the next act, the 'Angels' singer was pretending to mouth the script and was pulling a face. Classic stuff, Robbie.

But Dec had the last laugh when he said: "Out next act is a singing comedian, who says he takes the little things in life and makes them bigger. [turns to Robbie] You should have a word with him."

That certainly shut Williams up - although he did still have his trademark smirk.

Dec actually did such a good job last night that fans reckon he should carry on without pal Ant McPartlin for good. First he had to steer the juggernaut that is Saturday Night Takeaway and now he's shining on the BGT stage.

He opened last night's semi-final by performing 'There's No Business Like Show business', high-kicking and skipping his way down the aisles and onto the stage, chucking out a few high-fives and kissing some ladies as he went (what a LAD).

He told one woman: "You look nice," and she lost her mind a bit.

Dec even managed to find time to make a sly joke about his mate's absence from the small screen.

He stood next to the judges to introduce the duo of Dennis DeMillie and Marvin Muoneke, telling the crowd: "First up tonight we start with two men, who are absolutely inseperable.

"They're a double act everyone loved at the auditions and now they're back together for semi-final week.

"Must be nice."

The Geordie TV duo has been inseparable on screen since the PJ & Duncan days, 30-odd years ago, and we love them for taking the piss out of semi-famous people on I'm a Celebrity, Get Me Out of Here, and gatecrashing contestants' performances on Britain's Got Talent - especially when they do it uninvited.

There's been no word from Ant's camp of if/when he'll be able to return to our tellies.