The Insider.com

Robert Pattinson and Taylor Lautner make an appearance on The Ellen DeGeneres Show Friday to promote The Twilight Saga: Breaking Dawn - Part 2, and in this preview of their hilarious interview, Robert acknowledges that his fly is in fact always down.

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"I have a problem with that by the way," he says about being snapped multiple times with his zipper being down. "It's crazy. I noticed it yesterday as well. I said, what is wrong with me? It's actually become a problem."

Related: Kristen Stewart Finally Talks Relationship Status with Robert Pattinson

And though he doesn't offer up an answer as to why he's been so forgetful, he does come up with a solution.

"I'm just not going to wear pants," he jokes.

Speaking of showing some skin, Robert teases Taylor about his amazing physical transformation from the first Twilight film to The Twilight Saga: New Moon, which led to all those infamous shirtless shots.

"The gap between the first [film] and the second one was when Taylor….Taylor left the first film a 15-year-old little boy with a long wig and he came back like a Chippendale," he laughs. "It was crazy."

Though clearly, Taylor's more than a little embarrassed about his notoriously awful hairdo in Twilight.

"Oh wonderful, you had to show that one," he jokes as Ellen flashed a pic of a much skinnier Taylor. "Jeeze, kill me."

Pic: Robert Pattinson's Wax Figure is Hideous

Check out the video to hear Robert talk about Bear, his and Kristen Stewart's adopted dog. Robert and Taylor's appearance on The Ellen DeGeneres Show airs Friday, November 9.