Peter Egan discovered some unlikely pitfalls of joining the cast for the Downton Abbey Christmas Special - having to wear a kilt and crawl about in the mud for hours.

The 66-year-old actor stars as Shrimpie Flintshire, the nephew of Violet, Dowager Countess of Grantham, who plays host to his more well-known relatives at a Scottish castle for the Christmas Day episode.

Peter, who has had a lengthy TV acting career, but who is probably most fondly known as suave neighbour Paul Ryman in BBC sitcom Ever Decreasing Circles, revealed that as much as he enjoyed filming at Inveraray Castle, he was unprepared for certain experiences - namely discovering he'd be wearing a kilt.

"That gave me the horrors!" he recalled, laughing. "You have that thing about putting a skirt on, but in fact it looked very good."

Then there was the hunting scene with co-star Hugh Bonneville. "We had to go on our bellies and it was muddy and full of animal poo. Of course when you see it, it will be 30 seconds but we had eight hours of it!"

Peter revealed he didn't have much success with the Scottish dancing either. "But you'll be pleased to hear I'm not doing much of it," he joked.

However on the plus side, he enjoyed being part of the respected Downton cast. "It was just a great delight to work with Maggie Smith, one of my heroines from when I was a student," he said.

He added of his character: "He's a friendly, charming man and I haven't played many sweet men in my life."

During the trip, there's tension between the family and their hosts that's exacerbated by the frostiness between Shrimpie and his wife Susan. "They have a terrible relationship. They've lived together too long and they're tired of each other," Egan revealed.

:: Downton Abbey Christmas Special is on ITV1 on December 25.