VIDEO: Robert Pattinson on Ellen DeGeneres' Surprising Twilight Underwear Cameo

Ellen DeGeneres probably gives out her brand of underwear to hundreds of famous guests, but she probably never expected her undergarments to cause a big stir on the set of the blockbuster film franchise Twilight.

"I save your ones [Ellen underwear] for special occasions," Twilight star Robert Pattinson told the host on Wednesday's Ellen DeGeneres Show. "I was doing the last Twilight movie and I only had one pair left and they were those ones. We were doing this big fight scene and for some reason, I think the shape of my body, my back is too long or something, my a-- is constantly hanging out."

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However, not everyone on the set shared his love for DeGeneres, apparently. Pattinson said his constant, but accidental, semi-mooning made some producers on the crew suspicious, especially because of precisely what kind of underwear he was showing off.

"We were doing this big fight and every shot has these Ellen underpants. It came to a point where producers are calling up my agent going, 'I don't know what he is up to, but I don't like it,'" he said. "It's like they never questioned Fruit of the Loom before."

Watch the full interview: