Entertainment Tonight.

Funnyman Seth Rogen has been crushing on his co-star, the Knocked Up actor tells PEOPLE at the second annual Hilarity For Charity House Party in Los Angeles. No big deal, except that his co-star is Zac Efron.

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Married to actress, Lauren Miller, who attended the event with her husband, Rogen, 31, jokes that he can appreciate Efron's body.

"Zac Efron is incredibly handsome. He's the sexiest [expletive] on the planet!"

Rogen and Efron star alongside Rose Byrne, Dave Franco, and Lisa Kudrow in the frat boy movie, Townies.

"I did a scene with him, and we're both shirtless, and it was a very humbling experience," Rogen laughs. "I marveled at the fact that we're literally the same species."

The only department Rogen says he out-mans Efron is when it comes to man-hair.

"I'm hairier than he is, so I win at that," Rogen told PEOPLE.

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Townies has been shooting in Los Angeles and is set to release in 2014.

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