Taylor Lautner found the transformation of his New Moon character Jacob Black a challenge.
Jacob Black's a much bigger role in New Moon, the second movie in The Twilight Saga, and undergoes a physical transformation as he harbours a secret of his own.
In an interview with the Los Angeles Times the actor said: I read the book a couple of times before filming and I was really excited because Jacob's character in New Moon, he's like a split personality."
"Half of the time, toward the beginning, he's pre-transformation Jacob, where he's very sweet, very loveable, very outgoing. As soon as he transforms, he becomes a different person.
"I wanted to bring both of those sides of him to life. Also, as it's described in the book, he has three faces.
"The first face, the second face, and the third face is called the 'combined' face - that's where he is the new kind of conflicted Jacob."
The movie grossed $140 million in it's opening weekend in the U.S. and looks set to be one of the biggest box office hits of the year.
New Moon is out now.
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