George Clooney in Downton Abbey: First look pictures show Hollywood actor and Hugh Bonneville on Christmassy set for Text Santa special

Clooney will attempt to kiss the Dowager Countess in the charity sketch

George Clooney is set to bring a touch of Hollywood heartthrob charm to Downton Abbey in a charity sketch for the Text Santa fundraiser.

First look pictures show the Oscar-winning actor suited, booted and holding a clapperboard with Hugh Bonneville, who plays Lord Crawley in the ITV period drama.

Clooney, 53, will star as an American wedding guest in the special after filming his cameo earlier this year.

Lady Edith Crawley actress Laura Carmichael said that Clooney’s appearance on Downton was kept a secret from the cast, so much that they “didn’t know if it would actually happen” until the Gravity star turned up to shoot his scenes.

“It was amazing,” she told Metro. “We were filming and then heard, ‘He’s here! He’s here! He’s arrived!’”

Little is known about Clooney's Downton role but Carmichael revealed that he will try to kiss the Dowager Countess (Maggie Smith), causing her to swoon and end up on the floor.

Bonneville is reportedly friends with Clooney after the pair worked together on war film The Monuments Men, released to mixed reviews earlier this year.

Funds raised by Text Santa will go to Guide Dogs, Teenage Cancer Trust, Marie Curie Cancer Care, Alzheimer's Society, Together For Short Lives and WellChild.