When you’re pushing seventy years old, it’s a good idea to have a stunt double (or two) on the action movie you’re working on. But as his role was unique in the Lord of the Rings trilogy (and now The Hobbit), he needed a different sort of stand-in as well.
The guy on the left is his stunt double from Return of the King, the guy on the right is his size double for all the scenes where it needed to look like he was towering over the hobbits. Combine the gargantuan size of his double (McKellen is 5’11) with expert camera trickery, and the result was nearly flawless on film. I wonder if this guy is still around for The Hobbit trilogy?