Why Bradley Cooper Went Commando to Meet President Obama

Feb. 18, 2014 — -- Bradley Cooper better buy himself a new tux before the Academy Awards on March 2!

The Oscar-nominated actor, 39, admitted that when he attended the State dinner on Feb. 11 in Washington D.C., he did so without any underwear.

"So, I'm prepping for this new movie and I'm trying to gain weight fast," he explained to Ellen DeGeneres. "I've gained about 15 pounds in four weeks and nothing fits me anymore."

See: Leonardo DiCaprio and Bradley Cooper Bring Their Moms to Golden Globes

He continued, "So I wore the tuxedo I wore to the Golden Globes. I just sort of threw it in the bag and brought it and went to Washington, D.C. Then I'm getting dressed like 10 minutes before I was supposed to go, and literally the pants go up to like here," he mimed to his mid-thighs.

Cooper revealed that he could barely stand up to shake hands with the Secretary of State and other dignitaries.

"This is hilarious. I'm going to meet the president," he said he told himself while getting ready. "So I had to go commando number one cause there was no room at all. I did. I had to."

Watch: Bradley Cooper Moves in With Mom After Dad's Death

The "American Hustle" star said, "It was a nightmare, but I made it through."