Bradley Cooper definitely let loose at the White House State Dinner on Feb. 11!

The Oscar nominee revealed to Ellen DeGeneres that he was forced to go without underwear to the black-tie event!

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

The actor is reportedly trying to gain 35 pounds to play U.S. soldier Chris Kyle in "American Sniper."

"So I wore the tuxedo I wore to the Golden Globes," Cooper continued. "I just sort of threw it in the bag and brought it and went to Washington, D.C."

But like any good wardrobe malfunction, Cooper's happened at the last minute! "Then I'm getting dressed like 10 minutes before I was supposed to go, and literally the pants go up to like here," he said, pointing to his mid-thighs.

"So I had to go commando number one cause there was no room at all. I did. I had to," shared the "American Hustle" star, all while thinking, "This is hilarious. I'm going to meet the president."

bradley cooper

Cooper with girlfriend Suki Waterhouse at the State Dinner

In fact, Cooper said he could barely stand up to greet dignitaries or other guests at the dinner. "It was a nightmare, but I made it through," he laughed.

"How tight were they?" DeGeneres asked. "They were crazy-town tight," exclaimed the actor!

Watch the clip below!