Kellan Lutz ate 16 eggs a day and threw rocks to gain muscle for his role in 'Immortals'.

The actor put on 25lbs of muscle for the role of Greek god Poseidon by following a punishing work-out routine which he devised himself, training mainly on the beach rather than in a gym.

He told Men's Fitness magazine: "I don't really like the gym. I like to fool my body. I run around the beach and then there's scaffolding so I can just do different pulls-ups there.

"I ate 16 eggs every morning. I got up to 220 pounds of solid muscle. We'd work out every day. Shooting one scene could take all day - and when that's just driving a Humvee at five miles an hour, we had energy to burn."

'Twilight' hunk Kellan also trained with co-stars Henry Cavill and Mickey Rourke during filming, with them all challenging each other better themselves.

He added: "We were doing push-ups on top of the Humvees. We were throwing Wheels and rocks. We were timing each other, betting who can do the most push-ups, just to keep our sanity. 

"Within 30 minutes, you're dripping. And it's Africa. We pushed each other to be the best we could be."

Kellan, 26, underwent rigorous weapons training for the film, but it was worth it as Posiedon - god of the sea - has been one of his favourite characters to play.

He said: "There was training with a staff, yes. That was fun. I've done a lot of training. I love action movies and I've been trained in a lot of mixed martial arts, but nothing with the staff. We had really great trainers.

"It's a dream role for me. I just love my character. We're youthful. If you're a God, you might as well be at your physical and mental peak."