I was reading the booklet on the making of BBC Pride and Prejudice and found this comment by Mr Colin Firth that made me laughed.

He says he had begun to appropriate the character of Darcy and sort of felt that owned him. So much so that when all the actors were summoned for a read-through and he was surrounded by all these fantastic characters making everybody laugh he was thinking,
'Well. I was dull.'
Moreover, he began to notice that not a soul came up to him. He knew one or two people and talked to them, but he would say out of cast of over fifty people, very few seemed willing to talk to him. It then occurred to him that because he was playing Darcy he had to work quite hard to convince people that he would be friendly during the film!!