There’s a price to pay for being an awesome guest star on many of the coolest sci-fi and fantasy shows on television, and Mark Sheppard knows that price more than anyone. “I’ve become a liar,” he told BuddyTV.

Indeed Sheppard, who has had roles on everything from Battlestar Galactica and Firefly to 24 and Medium, and who can currently be seen as Crowley, the King of Hell, on the CW’s Supernatural, is an expert liar. When Crowley was seemingly killed back in December, he knew his character was still alive, but he had to lie to everyone he talked to about it. When I spoke to him, he wouldn’t even tell me where he was or what he was eating because any clue to his whereabouts might tell fans what show he’s currently working on, which could spoil a big surprise reveal.

Talking about his recent key guest appearance on the two-part season premiere of Doctor Who, Sheppard explained that he told a crowd of people that he would love to work on the show, only to leave, hop on a plane, and go to the Doctor Who set to film his role.

However, that didn’t stop me from asking about his work on Supernatural, where fans recently learned that his character has been secretly working with the angel Castiel in an unholy alliance. Sheppard was typically tight-lipped about anything that might happen in this week’s pivotal episode, “The Man Who Would Be King,” but he had plenty to say in praise of Supernatural‘s cast and crew.

The episode is written and directed by Ben Edlund, who also wrote Sheppard’s first episode on the show in season 5, creating the character of Crowley. But Sheppard is also a fan of Edlund’s work outside of Supernatural, calling his earlier animated series, The Tick, “One of the greatest cartoons ever made.”

Sheppard recognizes that it’s the passion of the Supernatural cast and crew, from top to bottom, that make this show different than many of the other great shows he’s been on. He described a meeting he had with the late Kim Manners and was impressed with how glowing and enthusiastic Manners was about Supernatural.

But Sheppard knows what one force makes Supernatural so beloved by fans. “The boys,” he said, referring to stars Jensen Ackles and Jared Padalecki. “The boys are truly fantastic.” Even six seasons in, they’re still as passionate about the work as ever.

In describing his favorite moment as Crowley, Sheppard pointed out the character’s recent turn into more physical activities like slitting throats. He particularly enjoyed one scene where Dean became disgusted by Crowley’s violence, which struck him as funny that Dean would choose that moment to get squeamish.

Supernatural fans will get to see and learn a lot more about Crowley with this week’s episode as well as the season 6 finale on May 20, but beyond that, Sheppard had little to say. Will Crowley stick around? Will Sheppard return to Doctor Who as quirky federal agent Canton Everett Delaware III? Is he secretly a robot sent back from the future to make awesome guest appearances on every show on television? There’s no way to know for sure, because Mark Sheppard is a liar, which is the reason why he’s so good at what he does.

(Image courtesy of the CW)

John Kubicek

Senior Writer, BuddyTV

John watches nearly every show on TV, but he specializes in sci-fi/fantasy like The Vampire DiariesSupernatural and True Blood. However, he can also be found writing about everything from Survivor and Glee to One Tree Hill and Smallville.