VIDEO: Robert Pattinson's Haircut a Medical Necessity

Robert Pattinson, currently sporting a severe-looking crew cut, has explained why he chopped off his famous locks.

"I got a terrible infestation of nits and I had to shave it all off," R-Pattz joked to Ellen DeGeneres on Wednesday's episode of her talk show.

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Although he went on to reveal the true reason for the cut: He trimmed three days ago for his role in Water for Elephants with Reese Witherspoon.

Meanwhile, the shy Brit opened up about his fear of talking in public."I just like doing things where you have a little time to think about what you're saying," he said.

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"I've always had a problem actually thinking before I open my mouth. Yeah, being spontaneous or just thinking. I have a problem with thinking."