It is a bit disappointing when Ian McKellen enters the room out of costume - speaking to the actor in full Gandalf garb would undoubtedly provide something of a thrill - but as soon as he begins speaking all regrets melt away.

"Hello," he says as he introduces himself to each of us in turn. "Hello, Orlando. Have we met before?"

"I...don't think so," the reporter answers.

"You can't even remember. All right. Nice to see you. Hello."

Introduced as "Sir Ian McKellen," the actor wears a pink scarf and glasses above a blue jacket, skinny black jeans and polished dress shoes that shine brilliantly in the light. He is a warm, thoughtful presence, reclining on a couch as he fields questions from the assembled group on the set of Peter Jackson's "The Hobbit: The Desolation of Smaug," his long, deliberative answers shot through with a delightful wit and self-deprecating sense of humor. It is difficult to know when he's finished talking - his speech is punctuated by lots of long, contemplative pauses - but rather than serving as a point of frustration this is somehow just another component of the two-time Oscar nominee's irresistible charm.

In order to distill our lengthy talk with McKellen into the most informative, interesting and/or amusing bits, we've put together a list of 10 pertinent highlights from the wide-ranging conversation below.

1. On the differences between Gandalf the Grey and Gandalf the White: "Well, there are two Gandalfs. There's Gandalf the Grey, who was in 'Lord of the Rings: Fellowship of the Ring,' and Gandalf the White who was in the other two films. And our favorite, Peter and my favorite, was Gandalf the Grey. We liked...his human qualities and he is the guy who liked to visit Hobbiton because he had a good time there, as well as going about his business. Gandalf the White is very focused and a commander. He had a short beard as if he meant business. He's a bit of a stick. You know that expression? A bit formal, but very concentrated on saving the world...well, fair enough. Now we're back with Gandalf the Grey...meddlesome, trouble, good humor, generous. And dirty clothes, dirty fingernails. So it's back with him now."

2. On figuring out which dwarf in the film is which: "I know the actors' names, but which actor plays which, not really...can you imagine being sent a script and told that your thirteen main characters are dwarves? Well, you wouldn't make the film, would you? No. It is a ludicrous enterprise, really, from that point of view. It had so many problems with it, this story. One of them is, 'will the audience ever work out who Ori, Nori and Dori are?' Yeah, they will. They'll know immediately. That's what's brilliant about that, the design and the acting. You'll have no problem at all. Sorry, what were you saying?"

3. On hobbits vs. dwarves: "The spirit of the four hobbits in 'Lord of the Rings,' I suppose I miss that. But they were the center of the story, but now the center has shifted. I don't think anyone could love the dwarves like we loved the hobbits."

4. On making the decision to come back: "I don't like to play a part that I have played before...Now here I am, back doing it specifically, that's actually the same person. And it is a long commitment, and at my age I have to decide, 'Do I really want to do this? Do I really want to go on this journey? Because if not, I can go on another journey.' So there was a lot inside me saying, 'No, no, no, what's the point? I've done it. Am I going to enjoy it? Am I going to find anything new in it?'

"And against that, what persuaded me was could I bear the thought of somebody else playing Gandalf? Because it's easily done. You put anyone in the outfit and they look like Gandalf. Not that clever. And a friend who said, 'Ian, just think of those fans,' who I am always going on about. I meet these little people, these eight year olds who love Gandalf. They love him. Not me, him. And she said, 'You have to do it for them, don't you?' And that cleared my mind totally, so yeah. I couldn't actually face talking to an eight year old and explaining why I didn't want to be Gandalf again. Because he wanted me to be."

5. On his "forbidden romance" with co-star Cate Blanchett: "Well, Cate Blanchett. Her husband doesn't know but she and I are going to get married quite soon. Which will surprise a lot of people. But you see, we only met at a party [during the making of 'The Lord of the Rings'], we weren't on screen together. Well, we were on screen together but we didn't meet. Here, we had a whole week, or maybe two. That was a thrill because she's a great screen actor and a very congenial person, for me. She's based in theater. That's her main job at the moment, running a theater. So there wasn't a moment that we didn't have stuff to talk about."

6. On Gandalf's grooming habits: "Funnily enough, he's got a smooth chest, but you never see it in the movie. The one disappointment is that Peter had half-promised, he may not remember, but at some point we said, 'Wouldn't it be fun to see Gandalf getting up in the morning?' And Peter's always saying he likes the guy who does sleep under a hedge and gets up and saves the world. Yes, so do I.

"But we do have a scene briefly where Gandalf is seen to be washing. And it's about time someone in Middle-earth washed. I had, I thought, the brilliant idea of, 'Why doesn't Gandalf have a huge pack on his back?' You know, with all the things you need when you are travelling. 'That would look ridiculous.' 'Okay.' So I said, 'Well, why can't I keep everything in my hat?' So if he was hungry, he just went in and out came an apple. Or a sandwich. Or a toothbrush. Or a razorblade. Oh, he doesn't use a razorblade. Except on his chest."

7. On how Gandalf takes a pee: "We see the dwarves eating a lot and drinking a lot. They never seem to go to the loo. I suppose it's those costumes. Perhaps they have some machinery inside I don't understand. And it's easy enough for Gandalf to relieve himself, it's just a gown. Lift it up. Sometimes don't even bother."

8. On his frustration with being asked to film his scenes with the dwarves separately from the other actors: "It was pretty severe to begin with, acting with fourteen other people who weren't in the room. Doesn't make for spontaneity, really...But Peter's been very good and has reduced that sort of filming to the minimum. The other day Martin Freeman was walking in a shallow ditch so that he would look smaller. Well, that's lovely, because I'm allowed to look at him then. But it was true in 'Lord of the Rings' I never got to look Elijah Wood in the eyes. We were never in the same place to do that. I was always looking at the mask of his small-scale double and he was always looking at a big pole, seven foot two. So in this film, Peter's managed to allow us to act together in a way that we didn't before. So my early worries were attended to, yeah."

9. On why you will never see Gandalf drunk:
"The only slight disagreement Peter and I had was when the dwarves were making merry at Bilbo's house and Gandalf was looking on fairly approvingly, drinking red wine. He was offered tea but he asked for red wine, that was in the book. And Peter said, 'Just make him a little tipsy.' I said, 'I'm going to have to put my foot down. Gandalf does not get drunk.' I think Gandalf can drink everyone under the table. The mind is always clear, always questing. So you will not see a tipsy Gandalf, although it was requested."

10. On what's different about Gandalf this time around:
"The first thing I was given was a new nose. So the sharp-eyed will see that Gandalf doesn't look the same...I can't see the difference, but there is, apparently. There is one, apparently. No, the wig is the same, the beard is the same, the makeup -- [makeup artist] Rick Findlater, fortunately, is the same. So we're back trying to look the same. ...Everyone says, 'Oh, it's remarkable, and you look exactly like you did in 'The Fellowship of the Ring.' No, I don't. I'm thirteen years older and it shows."

"The Hobbit: The Desolation of Smaug" hits theaters on December 13.