When Kellan Lutz joined “The Expendables 3,” Sylvester Stallone made sure he wasn’t going to be outshone.
“I was bigger because of ‘Hercules’ and now that I was actually wearing clothes, Sly was like, ‘You don’t have to work out so much. Don’t worry about it!’ ” Lutz tells The Post of his co-star’s joke.
In reality, Lutz is as beefcakey as ever in the film series’ third installment, hitting theaters this Friday. The franchise that has famously teamed up fading action stars for one big butt-kicking spectacle returns with legends Stallone, Arnold Schwarzenegger, Dolph Lundgren and a whole bunch more. Lutz joins the cast as a young buck, and this time around the mercenary group battles it out with a dangerous arms dealer, played by Mel Gibson.
For Lutz, who plays a Navy SEAL recruited to the group, just being around all those marquee names was the stuff dreams are made of.
“A lot of the young guns, when we weren’t working, we just wanted to be on set to watch the ‘men’ work — the veterans, the legends,” he says.
He may not be a legend just yet, but it’s hard to argue that Lutz is anything but a man with a capital M. The 29-year-old star, born in North Dakota, first appeared on TV screens with bit parts before breaking big with the “Twilight” franchise. As Robert Pattinson’s brother in the movies, Lutz stood out thanks to his larger-than-life physique.
In turn, his career began to take a pretty specific path.
“There’s never going to be a time where they’re like, ‘Oh you’re too big for an action movie, you’re too ripped,’ ” he says. “[But for others,] I have been told you’re too big, you’re too pretty, you’re too tall — everything. You’re never going to be perfect for every role, and that’s why you just have to stay true to what you enjoy.”
Lutz is hardly a dumb jock — the guy studied chemical engineering at Chapman before pursuing acting.
“I don’t mind — people can judge a book by its cover,” he says. “As long as you stay out of the paparazzi and the press and you’re more known for your work than your personal life, there’s still a bit of mystery there.”
Lutz still carries a passion for learning — on set, he can regularly be found reading science books. He’s also working on some patents, though he’s coy as to what they are.
“It’s great to have my acting world and also work on some of my chemical compounds and mixtures,” he says. “I can’t really talk too much about it, but we’re almost there.”
Lutz has also been hard at work on bigger movie parts. He starred in the title role of “The Legend of Hercules” in January, though the film grossed just $19 million domestically.
“Maybe it didn’t open to what we wanted it to do, I don’t care,” he says. “I’d love a huge blockbuster. That day will come whenever I get to play one of my other favorites, like He-Man or Venom.”
Already in the bank is next year’s “Experimenter,” about the famous obedience experiments at Yale. He’s also set to reprise his pre-fame part in the cult show, “The Comeback,” returning this fall to HBO. But he’s also got something else on his mind.
“My dream would be … doing it all the way up to ‘Expendables 7, 8, 9, 10,’ ” he says. “I would love to be the veteran Expendable.”