To some, he's the demon Crowley. To others, he's a backwater merchant known as Badger.

Regardless of how you know him, actor Mark Sheppard is about to take on another iconic genre role : this time in the United Kingdom.

Sheppard has signed on for a role in the upcoming sixth season of BBC's "Doctor Who." No details have been revealed on the role yet, only that he will play a character called Canton Everett Delaware III, a role the Beeb described as "huge," playing a major part in a two-episode story.

The actor was scheduled to appear at ValleyCon 36 in Fargo, N.D., however he had to pull out of the event when he got word that he will step into the Tardis for the two-part season premiere.

"We had just booked Mark's airline tickets a week ago when less than 12 hours later he got the dream job of any kid who grew up in England," ValleyCon 36 explained in a statement. "He [has] landed a huge role in the new 'Doctor Who.'"

Filming commenced last week on the sixth season of the series, which will see Matt Smith reprise his role as The Doctor along with Karen Gillan and Arthur Darvill as his trusted companions. Production already is complete on the 2010 Christmas special, and the episode already is being teased as a standalone adventure with a twist.

In addition to being a festive adventure filled with all the seasonal cheer, the Christmas special also will serve as a prelude to the new season and set a few threads in motion. The storylines touched on in the festive adventure is the "silence," which was hinted at in the final episode last season. The opening two episodes of the season will be based in the United States with filming being carried out in Utah.

The episode will air in the United Kingdom on Christmas Day, and in North America before the end of the year. Season 6 is then expected to air its first seven episodes in the spring before the show takes a summer break and returns in the fall.