Which Celeb Forgot to Button His Pants?

Star steps out on set with his pants undone...find out who forgot to fix their fly

This actor obviously wasn't ready for his close up (at least, his crotch wasn't) when he stepped out on the set of his latest movie with his fly unbuttoned yesterday.

Let's hope someone from wardrobe noticed this snafu before cameras started rolling.

Think you know who forgot to fasten his pants? Find out after the jump...

It's Ryan Phillippe on the set of The Lincoln Lawyer, where he's cast as a Beverly Hills playboy.

Sounds like the role is a real stretch! Last night, Ryan hit the Fat Tuesday pre-ESPY party sponsored by Hennessy Black, where he was spotted dancing closely with his latest model girlfriend, Alexis Knapp.

"They couldn't keep their hands off each other," a source tells me. "The only time they came up for air was when Big Boi performed."

The new twosome stayed at Blvd3 until 2 a.m. Hope Ryan didn't have an early call time today!