02/18/2014 01:20 pm ET Updated Feb 18, 2014

Bradley Cooper Went Commando To The 2014 State Dinner

Bradley Cooper scored an invite to the 2014 State Dinner, and he learned a hard lesson about the importance of trying on clothing before the big day.

The "American Hustle" actor revealed to Ellen DeGeneres that his outfit for the night was so tight he had to forgo underwear in order to get his trousers up over his hips.

Cooper put on 15 pounds in the last four weeks, in preparation for his upcoming role as Navy SEAL Chris Kyle in "American Sniper," and, as he told DeGeneres, "nothing fits [him] anymore." Cooper arrived in Washington DC for the dinner, and prepared to suit up in the tuxedo that he wore just a few weeks ago to the Golden Globes. He found, however, that the pants which fit him fine so recently had become "crazy town" tight, due to his weight gain.

"I had to go commando," he told Ellen, while the crowd erupted in cheers. "It was a nightmare, but I made it through," he laughed. Cooper then mimed the awkward and uncomfortable movements he was forced to make that night in order to stand up and sit down without splitting his pants.

Cooper plans to gain 20 more pounds before filming "American Sniper," so he'll definitely have to do some shopping before attending his next black-tie event.

Cooper wasn't the only celebrity to attend the presidential bash. Julia Louis-Dreyfus, Mindy Kaling and Stephen Colbert also made appearances at the event.



Bradley Cooper