AceShowbiz - Actor Paul Rudd was left red-faced during a recent meeting with U.S. President Barack Obama - after failing to pick up on a joke. The "I Love You, Man" star took in a tour of the White House with his movie co-star Reese Witherspoon while shooting new romantic comedy "How Do You Know" in Washington, D.C. and they were treated to a meet-and-greet with the top politician.

But the actor messed up the big moment by mistaking a quip cracked by the President for a serious comment. Rudd explains, "We were in the Oval Office and I'd just broken into a sweat. I was nervous..."

"He said, 'Who do you play (in the film)?' And I said, 'I play this guy, he's getting indicted...' And he goes, 'Oh, so you're playing a congressman?' And I was so nervous that I said, 'Actually, no, I'm in a business with my father...' And he says, 'That was a joke.' I'm like, 'Oh God, of course it was!' "