Will Ferrell and Bear Grylls

Stars often go to shameless lengths to promote their movies, but Will Ferrell's Man vs. Wild stunt has raised the bar.

The funnyman will appear on the show Tuesday night (10 pm, Discovery Channel) in a cross-promotional stunt for his new movie, Land of the Lost. The show features Ferrell and host Bear Grylls during 48 hours in the subzero temperatures of the north Sweden wilderness.

In the episode, Ferrell is lowered into the wilderness by rope from a helicopter before hiking with makeshift snowshoes through waist-high snow. He then spends the night with Grylls in a cave, dining on grilled reindeer eyeballs from the head of a carcass.

"Nine out of 10 actors would not do that," Ferrell told the Associated Press.

Ferrell, who was unfamiliar with the show, was reluctant at first, but said after watching an episode that "this could be too crazy to say no to."

Ferrell's trademark goofiness is still on display. In one scene, the actor scarfs down a Twinkie that Grylls packed for emergencies as soon as the host turns his back. But Ferrell said he wasn't always thinking about comedy.

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

And how did those eyeballs taste? "It's like a gelatinous piece of rock," Ferrell said.