David Jason is to make his debut in an original Sky One drama commission, in an adaptation of one of the best-selling novels of Terry Pratchett.
The Only Fools and Horses star will play Death's servant Albert in the semi-medieval fantasy drama Hogfather, part of Pratchett's long-running Discworld series.
Jason's signing is quite a coup for Sky. Now seen most regularly in ITV's A Touch of Frost and one-off dramas such as The Quest, he is British TV drama's most bankable star.
The two-part film, which will run for a total of four hours, will be part of Sky One's 2006 Christmas schedule. It is the first Discworld film to be turned into a live action movie and will be filmed in high definition.
"I am thrilled to be taking part in Hogfather," said Jason. "I am a huge fan of Terry Pratchett's books and to play the part of Albert is going to be great fun."
Pratchett has sold more than 41m books worldwide and is the UK's second most popular contemporary author, behind Harry Potter creator JK Rowling.
Hogfather is set in the midwinter festival of Hogswatch, when the jolly fat man, the Hogfather, traditionally delivers children's Christmas presents.
But the Hogfather goes missing and his place is taken by another supernatural power, Death, who disguises himself with a false beard and a few cushions up his jumper. It is up to the hero of the story, Susan, to find out what has happened to the real Hogfather.
The drama, which has been in development for a year, is being filmed by the Mob Film Company in Romania, with computer-generated effects by the Moving Picture Company.
Hogfather will be distributed internationally by RHI Entertainment, formally known as Hallmark Entertainment.
"Terry Pratchett is one of the most successful authors or our time and his fantasy fiction will strike a chord with Sky One viewers," said Elaine Pyke, the Sky One drama commissioner.
Joel Denton, the RHI Entertainment president, production and distribution, said the company would "continue to build our presence in the UK by producing more large event mini-series that utilises UK talent and best-selling novels".
Hogfather is being adapted for the screen and directed by Vadim Jean, whose big screen credits include Leon the Pig Farmer, and produced by Rod Brown (Dream Team, Goal) and Ian Sharples for the Mob Film Company. It will be executive produced by Ms Pyke and Robert Halmi.