MAN VS. WILD 10 tonight, Discovery Channel.

NEW YORK - The wilderness of northern Sweden, where Will Ferrell ate grilled reindeer eyeballs with adventurer Bear Grylls, seems like a long way to go to promote a movie and test-drive a television spinoff.

But that's where the two men were for 48 hours in early April, where the subzero temperatures made laughable the idea of spring. Their trip is chronicled on an episode of the Discovery Channel's "Man vs. Wild" series that debuts tonight.

Ferrell climbs out of a helicopter by rope ("Mommy!" he shouts), is eased down a cliff supported by two sticks wedged in ice, trudges through waist-deep snow on makeshift snowshoes of twigs and spends a night with Grylls in a snow cave. Dinner, and breakfast the next morning, comes from the head of a reindeer carcass found along the way.

Nine out of 10 actors would not do that," Ferrell deadpanned in an interview with the Associated Press.

Ferrell wasn't familiar with "Man vs. Wild," probably the looniest and most entertaining series in the adventurist genre, when his manager broached the idea. But the comic actor, who has run three marathons, warmed to the idea.

"I started watching it and thought, 'this could be too crazy to say no to,' " he said.

All in the name of promotion, too: the Discovery episode airs three days before Ferrell's movie "Land of the Lost" hits the theaters. Ferrell plays a scientist who has some close encounters with dinosaurs in a time warp adventure.

The "Man vs. Wild" episode is part a wider cross-promotion deal between Discovery Communications Inc. and the NBC Universal Movie studio. For instance, when the movie "Frost/Nixon" was released, Discovery's "Cash Cab" game featured questions from the Nixon era.

"I would have killed to have Will Ferrell out in the wilderness with Bear Grylls, even if we didn't have a movie to promote," said John Ford, Discovery's president and general manager.

The network was mulling the idea of a celebrity version of Grylls' show, and considers the Ferrell episode a successful pilot.

For adventurous stars, it undoubtedly has greater cache than a run on "I'm a Celebrity, Get Me Out of Here." But does it cheapen the "Man vs. Wild" brand, built upon Grylls' tips to survive forbidding environments? Ford said he didn't think so.

Grylls stows away a Twinkie for Ferrell to get some quick energy in a pinch. Of course, the actor downs it the minute Grylls first turns his back. The episode moves along briskly with Ferrell cracking wise ("I don't know how I got myself into this. I don't even like camping."), and Grylls reminding viewers of the life-threatening conditions.

"There were times when I thought, 'I'm too tired to be funny right now. I'm too tired to be cold,' " Ferrell said.

Despite the conditions, and stunts like trying to climb a frozen waterfall, Ferrell said he never really felt in danger. His toughest trick may have been his last: Having to use a rope ladder to climb into a helicopter at the end of the adventure.

"You had to use all your arm strength to get up," he said. "By the time I clipped in, I totally let go and was hanging upside down and laughing at myself, wondering how this was going to look like. But we figured it out and the next thing I knew I was flying 600 feet in the air, hanging out of a helicopter. It was kind of insane."

Discovery wasn't about to let several million dollars worth of Hollywood actor get in any serious danger. "I would say we had a special emphasis on safety this time," Ford said. "We definitely didn't want to have our first experience with a big star be a headline-seeking disaster."

Oh, and we were wondering about that reindeer eyeball. Does it, um, taste like chicken?

"Not even close," Ferrell said. "It's like a gelatinous piece of rock." *