In a season where shows have dropped like mayflies, FOX's supernatural drama "Tru Calling" has managed to stay on the air, despite overwhelming competition in its Thursday, 8 p.m. ET, slot from the dual powerhouses of "Friends" and "Survivor."

Eliza Dushku stars in "Tru Calling" as Tru Davies, a morgue assistant who can travel back in time 24 hours and prevent deaths. On March 25, the show gets a shot in the arm, as former "Beverly Hills, 90210" star Jason Priestley joins the cast for a seven-episode stint. He plays Jack Harper, a former EMT who joins the morgue staff, working under Tru's boss, Davis, played by comic Zach Galifianakis.

Priestley first became aware of the show while watching FOX pilots last summer.

Speaking one week from the end of his filming schedule, Priestley says, "'Tru Calling' was the one pilot that I said, 'You know what, this is a really good show. It's got places to go that are interesting. It can change every week.' So when they called me and asked me if I'd be interested in playing this new character they were bringing on the show, I said, 'Absolutely.'"

There is apparently more to Jack than meets the eye.

"I can't tell you too much about what I like about Jack," Priestley says. "A lot of what I like about Jack has yet to be revealed, oddly enough. It's all very secretive, in that very sci-fi way. It's so funny. I thought they were hardcore about it on '90210' -- not a bit. These sci-fi people take it very seriously.

"With Jack, I think if people are really paying attention, they'll be able to formulate some ideas as to what's going on."

Filming "Tru Calling" brought Priestley back to his native Vancouver, Canada, at the same time as former "Alias" regular Bradley Cooper, who is doing a six-episode run on USA Network's "Touching Evil." Late last year, the two were also in Vancouver, doing the ABC Family romantic comedy "I Want to Marry Ryan Banks."

"It was so funny when the two of us wound up in Vancouver again," Priestley says. "It was great."

Asked if the two found time to get into mischief, Priestley says, "No, we weren't in any trouble. We're working too hard, are you kidding me? How funny is Coop, though? Dude, he is so funny."

Apparently, Priestley also had a few laughs with Galifianakis. "Zach is the funniest human being on the planet. He is ridiculously funny. You work in a morgue, right? On the set, we laugh a lot. He always does it right before they call 'Action.' He drops a little one-liner on me. He's a mean man."

Priestley's arrival also meant a bit of a breather for Dushku.

"I think a big part of me being there," he says, "is to alleviate some of her workload. This whole first season, she's been in every scene, every shot, every day. That's a lot for any actor to take on."

As might be expected, Jack doesn't come to "Tru Calling" just to be window dressing.

"Jack's an interesting guy," he says. "He's very charming, very affable, very likeable. But you know, Jack has an agenda. There's a reason Jack showed up in the morgue. Suffice it to say, there's a reason, and that reason will become clear in the next few weeks.

"But he's not evil. There's no evil."

"Tru Calling" is just one of the shows this year -- along with Showtime's "Dead Like Me," CBS' "Joan of Arcadia" and FOX's new "Wonderfalls" -- in which either God or just mysterious omnipotent forces communicate with young women. So far, such forces don't seem interested in communicating with young men.

"Why would they?" Priestley says. "They could try to talk to young men, but young men wouldn't listen. There's a game on. 'Don't try to talk to me during a football game. What's the matter with you?' I understand it. I get it."

Because of his work on "Tru," Priestley wasn't involved in this year's round of pilot casting.

"It's OK," he says. "It's all fine with me. If 'Tru' comes back, then I come back with it. It's fine with me."