Murdoch Mysteries holiday special to feature Ed Asner, Peter Mansbridge

Film and TV veteran Ed Asner and CBC Newschief correspondent Peter Mansbridge are among the famous faces set to pop up in the forthcoming Murdoch Mysteries holiday special.

CBC announced details of A Merry Murdoch Christmas, the first-ever holiday special episode of the popular, early 20th century-set TV mystery series, onThursday morning.

"The thing that I like the most about having the opportunity to do a Christmas special is that it means Murdoch Mysteries has become one of those shows that is loved and admired by a strong loyal audience," saidthe weekly drama's executive producer,Peter Mitchell.

The show has seen a host of prominent guest actors join its cast over the years, from this season's earlierepisode starring WilliamShatneras Mark Twain to the July 2011 instalment featuringPrime Minister Stephen Harper as a cluelesspolice officer.

"I am married to an actor with years of experience on stage and in TV and movies doing news doesn't cut much with that crowd," notedMansbridge, who anchorsCBC'sThe National,making a reference to his wife, Cynthia Dale.

"I now finally have something to lord over her! I'm thrilled to be involved, even if it's for a very short cameo."

'A real romp'

Actors Brendan Coyle (Downton Abbey) and Kelly Rowan (The O.C.) are also among the guest performers set to join Yannick Bisson, Hlne Joy and the other Murdoch regulars for the two-hour special, currently in production andslatedto air Dec. 21.

The Christmas-themed episode revolves around the murder of a local business tycoon and philanthropist during the holiday season and the theft of his gifts for underprivilegedchildren.A further wrinkle turns up when the missing presents are foundin the possession of a man (Asner) claiming to be Santa Claus.

"It's a real romp, pretty epic, and I love what I've been asked to do," Coyle revealed to CBC News during a set visit earlier this fall.

The guest stint marksthe third Canadian acting gig for the British actor, a stage veteran perhaps best known for playing Lord Grantham'svalet John Bates on TV hitDownton Abbey.

"It's a very laid-back vibeand this is a well-oiled machine, this show," he said of the Murdoch set.

"I was a little nervous coming in this is my first day I have a big scene with Yannick, who plays Detective Murdoch and it was great. It went very smoothly...it's a happy set."

Murdoch Mysteries is based on the popular series of novels by Maureen Jennings. The series, which premiered in 2008, is currently in its ninth season.