First up, is a sneaky peek of the newly married actor in a brief video clip (above), which sees him playing a wedding guest and chatting with Rose and The Countess of Grantham.
The first official photos of the 53-year-old star's appearance have also appeared, which see him posing with Hugh Bonneville (Robert Crawley) on set.
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George Clooney on set with Hugh Bonneville
The official synopsis for the episode reads: ‘It’s Christmas at Downton and Lord Robert Crawley (Hugh Bonneville) seems to be facing financial ruin once again. He’s beginning to wonder if his family may be better off without him but divine intervention in the form of a very special heavenly body gives him a view of what life would really be like without his guiding spirit.’
When George filmed the scenes earlier this year, many of the show's female stars were reportedly queuing up to have the picture taken with the star.
Laura Carmichael, who plays Lady Edith Crawley, said: "It was amazing. We didn’t know if it would actually happen until he turned up.
"We were filming and then heard, ‘He’s here! He’s here! He’s arrived!'"
"There is a very brilliant moment with Maggie and George - and I don't know if I want to give away any more than that really - but Maggie does a very comedy fall," she said.
"George plants a kiss and Maggie ends up on the floor, it's wonderful. He was hilarious."
The full 'Downton Abbey' Text Santa sketch airs on ITV on 19 December.
George Clooney through the years
George Clooney(01 of53)
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George Clooney arriving for the UK Premiere of The Monuments Men, at the Odeon Leicester Square, London. (credit:PA)
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PARIS, FRANCE - FEBRUARY 12: George Clooney attends 'Monuments Men' Paris premiere at Cinema UGC Normandie on February 12, 2014 in Paris, France. (Photo by Julien M. Hekimian/Getty Images) (credit:Getty Images)
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MILAN, ITALY - FEBRUARY 10: (EDITORS NOTE: Image has been converted to black and white) George Clooney attends 'The Monuments Men' Milan Premiere on February 10, 2014 in Milan, Italy. (Photo by Vittorio Zunino Celotto/Getty Images) (credit:Getty Images)
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BERLIN, GERMANY - FEBRUARY 08: George Clooney speaks on stage at 'The Monuments Men' premiere during 64th Berlinale International Film Festival at Berlinale Palast on February 8, 2014 in Berlin, Germany. (Photo by Ian Gavan/Getty Images) (credit:Getty Images)
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BERLIN, GERMANY - FEBRUARY 08: George Clooney attends 'The Monuments Men' premiere during 64th Berlinale International Film Festival at Berlinale Palast on February 8, 2014 in Berlin, Germany. (Photo by Andreas Rentz/Getty Images) (credit:Getty Images)
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US actor George Clooney poses during a photocall for the film The Monuments Men at the 64th Berlinale Film Festival in Berlin, on February 8, 2014. The 64th Berlinale, the first major European film festival of the year, starts with 24 international productions screening in the main showcase. AFP PHOTO / JOHANNES EISELE (Photo credit should read JOHANNES EISELE/AFP/Getty Images) (credit:Getty Images)
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BEVERLY HILLS, CA - NOVEMBER 09: Actor/filmmaker George Clooney accepts the Stanley Kubrick Britannia Award for Excellence in Film onstage during the 2013 BAFTA LA Jaguar Britannia Awards presented by BBC America at The Beverly Hilton Hotel on November 9, 2013 in Beverly Hills, California. (Photo by Kevin Winter/Getty Images) (credit:Getty Images)
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BEVERLY HILLS, CA - NOVEMBER 09: Actor George Clooney attends the 2013 BAFTA LA Jaguar Britannia Awards presented by BBC America at The Beverly Hilton Hotel on November 9, 2013 in Beverly Hills, California. (Photo by Jason Merritt/Getty Images) (credit:Getty Images)
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HOLLYWOOD, CA - NOVEMBER 08: Producer George Clooney attends the premiere of The Weinstein Company's 'August: Osage County' during AFI FEST 2013 presented by Audi at TCL Chinese Theatre on November 8, 2013 in Hollywood, California. (Photo by Kevork Djansezian/Getty Images for AFI) (credit:Getty Images)
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NEW YORK, NY - OCTOBER 02: Actor George Clooney attends an official screening of 'Gravity' for Academy members hosted by The Academy of Motion Picture Arts and Sciences on October 2, 2013 in New York City. (Photo by Brad Barket/Getty Images for Academy of Motion Picture Arts and Sciences) (credit:Getty Images)
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VENICE, ITALY - AUGUST 28: Actor George Clooney attends the Opening Ceremony And 'Gravity' Premiere during the 70th Venice International Film Festival at the Palazzo del Cinema on August 28, 2013 in Venice, Italy. (Photo by Ian Gavan/Getty Images) (credit:Getty Images)