Seth Rogen (left) and Zac Efron
Christopher Polk/Getty; Kevin Winter/Getty
04/26/2013 at 01:00 PM EDT
On-set romances are commonplace in Hollywood. But the latest big costar infatuation is less The Notebook
and more Beauty and the Beast
shares the screen with the stunning Rose Byrne
in the upcoming comedy Townies
. But surprisingly, he has his eye on another actor entirely.
is incredibly handsome," Rogen, 31, told reporters recently at the second annual Hilarity For Charity House Party in Los Angeles. "He's the sexiest [expletive] on the planet!"
Acting beside the buff Efron, 25, was a challenge, says Rogen, particularly at one point during the shoot.
"I did a scene with him, and we're both shirtless, and it was a very humbling experience," Rogen said with his trademark chuckle. "I marveled at the fact that we're literally the same species."
Still, Rogen found a degree of solace in knowing that he beats Efron on one score, at least.
"I'm hairier than he is, so I win at that," the actor told PEOPLE as he clutched his wife
, Lauren Miller, to his side. "[Zac's] very veiny. I'm not that veiny."