AceShowbiz - Taylor Lautner struggled to act out fight scenes with Robert Pattinson in the latest "Twilight" movie because he's such good friends with his co-star. The actors had to film sequences for "The Twilight Saga's Eclipse" in which their characters, Jacob Black and Edward Cullen, become embroiled in a clash over Kristen Stewart's alter-ego Bella Swan.

But Lautner found it difficult to act angry at his pal - and they couldn't get through the scenes without giggling. He tells Access Hollywood, "One of the most challenging things about filming this was having to hate Edward, because I'm looking at Rob and it was difficult."

"Every time we'd have a shouting match or he'd grab me on the shoulder or something, as soon as they called cut, we'd bust out laughing. Or we'd ruin plenty of takes."