'Lord of the Rings' star Ian McKellen is sick of Harry Potter fans mistaking him for Dumbledore.

Sir Ian McKellen

Sir Ian McKellen

The 79-year-old actor's most famous role is playing the wizard Gandalf in Peter Jackson's fantasy trilogy but he is constantly pestered for photos and autographs by confused Potter fans who think he played the head of Hogwarts Dumbledore.

And McKellen says Dumbledore actor Sir Michael Gambon - who played Harry Potter's mentor in six films - has the same problem with 'LOTR' fans thinking he's Gandalf all the time.

Speaking on 'David Tennant Does A Podcast With...', McKellen said: "I used to be very shy, to go to a party to me was misery because I didn't feel I could talk to anybody ... When I should have been meeting people I'd be sitting in the corner waiting for it to be over. "Now I can walk into a room of strangers almost anywhere in the world and they'll be somebody who knows who I am and be happy to meet me, well that's a wonderful way for a shy person to go into a room now.

"Although half of them think that I'm Dumbledore! "Which I'm not. I said to Michael Gambon, 'Do you ever get mistaken for me? Because I'm often mistaken for you.' He said, 'Oh, yes. They give me their wretched photographs and I sign your name.'"

McKellen - whose other famous big screen role is playing Magneto in the 'X-Men' franchise - is very proud to be beloved by millions because of his portrayal of Gandalf from J.R.R Tolkien's books because it has allowed him freedom to work on issues close to his heart.

He said: "I'm allowed to go to all sorts of places because of Gandalf.

"They let me into schools as Gandalf and by the time I've finished talking they might think, 'Why have we let this old gay man talk to our kiddies?'

"It's because he's talking about something that concerns children who are growing up gay, or having friends who are gay or having parents who are gay. "The more it's talked about the better, because the less remarkable it becomes.

"And I don't feel I've cheated, because if someone says, 'Anyone who played Gandalf would have been a success.' I think that's true. We were always making jokes, if I was feeling a bit off colour we'd say get John Hurt in. I think I've earned the right to call myself an actor because of the work I've done, but it wasn't that difficult playing Gandalf.

"It is lovely to have a catchphrase, I have a catchphrase, 'You shall now pass!' I've always thought it would be lovely to be like Bob Hope or Morecombe and Wise and as you walk on stage they play your signature tune, I wish I had a signature tune."