Sir Ian McKellen had a special Halloween message for the people of the internet this afternoon.
The actor, who has never been afraid to take the piss out of himself a bit took to Twitter today to let everyone know what he was going to be dressing up as this Halloween. He has plenty of options in his wardrobe we presume, so long as they let him keep the Gandalf and Magneto costumes.
— Ian McKellen (@IanMcKellen) October 31, 2014
The whole thing is a reference to the picture (which is a fake) of him wearing a t-shirt that says he's both Magneto and Gandalf, which has become a meme. Good internet knowledge from Gandalg/Magneto there.