Out British actor Sir Ian McKellen has rejected calls for gay characters to only be played by gay actors.

McKellen, 82, is best known for playing Gandalf in The Lord of the Rings and The Hobbit trilogies and Magneto in the X-Men films.

Speaking with the BBC's Amol Rajan, McKellen argued that acting is pretending.

"Is the argument that a straight man cannot play a gay part, and if so, does that mean I can't play straight parts and I'm not allowed to explore the fascinating subject of heterosexuality in Macbeth?” McKellen rhetorically asked.

"Surely not. We're acting. We're pretending. Now, are we capable of understanding what it is to be Jewish? Are we going to convince a Jewish audience that we're Jewish? Perhaps we don't need to because we are just acting," he said.

McKellen also said that he wishes he had discussed his sexuality with his late father.

"The idea that he couldn’t have coped with the fact that his son was gay is inconceivable to me, even though I’m not aware that we had any gay friends or that he’d ever thought about it or that it had any impact on his life," McKellen said.

"Therefore it might have come as some sort of surprise to him, but there would have been no moral judgment." he added.