Finally, there's evidence that George Clooney really has been hanging out with the Crawley family. Hurrah!
The 53-year-old actor joins Downton star Hugh Bonneville in a photo taken from the set of the Text Santa fundraising special.
George and Hugh, who worked together on the film The Monuments Men, can be seen posing in matching grey suits - but ITV has also given us a sneak preview of the Clooney episode with this 19-second clip....
He looks quite at home, doesn't he?
Turns out, the rest of the cast didn't even know the Hollywood star would be making a cameo appearance.
"It was amazing. We didn't know if it would actually happen until he turned up," Laura Carmichael, who plays Lady Edith Crawley, told The Mirror.
"We were filming and then heard, 'He's here! He's here! He's arrived!'"
Earlier this year it was reported that Clooney and his fiancée, Amal Alamuddin, considered choosing Highclere Castle, the Hampshire estate where Downton Abbey is filmed, as the venue for their wedding.
However, it's thought this was just a cover story to keep his Downton appearance a big secret. Clever.
Love George? Who doesn't? Flick back through his style evolution below:
In other George Clooney news, it sounds like the newlywed has been splashing out...