Clooney will play a “very special heavenly body” who guides Lord Robert Crawley (Hugh Bonneville) out of a Christmas crisis. He will star alongside “Downton” regulars Elizabeth McGovern and Lily James, who play Lady Cora Crawley and Lady Rose, respectively.
Clooney and Bonneville reportedly became friends while filming “The Monuments Men,” which bowed in theaters in February.
The sketch will air during the three-hour charity special, which will also feature U.K. personalities Ant and Dec, Phillip Schofield, Christine Bleakley, Paddy McGuinness and Alesha Dixon, among other surprise celebrity appearances.
“Text Santa” will air at 8 p.m., Friday, Dec. 19 on ITV. Proceeds will benefit the Teenage Cancer Trust, Guide Dogs, Marie Curie Cancer Care, Alzheimer’s Society, WellChild and Together for Short Lives.
“Downton Abbey” returns to PBS on Jan. 4.