Interview: Night At The Museum 2 star Hank Azaria

The cast of Night At The Museum 2 were in London for the movie's launch and I got a chance for an exclusive chat with Hank Azaria – who, as well as having a very successful film career, provides the bulk of the voices for The Simpsons.

The film marks the fourth time Azaria has starred with Ben Stiller, having appeared with him in Along Came Polly, Dodgeball: A True Underdog Story and Mystery Men.

Stiller told me of the choice: "Hank can basically do anything with voices and characterisations, and with Kahmunrah he found the perfect balance between playing a truly evil villain and being really funny, too."

Azaria actually told me that the basis for his accent in the film was screen legend, Boris Karloff: "Yes and no, it's actually an interesting story to me. We knew he would have an English accent because he's the brother of Ahkmenrah from the first movie. Kind of bold and aristocratic is how we started, sort of laid back and bored. We did the table reading that way and then the head of the studio actually had a good, creative idea.

"Tom Rothman said 'you're a voice guy, can't we push it a little?' We were reluctant to, and then I went for a wardrobe test and while there, getting the costume on film we tried four or five different versions of the character, really weird versions.

"And at the last minute I went 'what about Karloff, he was a mummy', and did it as a joke really."

So now you know where the voice comes from!

Hank has an incredible repertoire of voices and I asked him whether working on The Simpsons had helped him to improve his repertoire: "I used to, before I used them all up on The Simpsons. I'm serious. Now everything I've done or can possibly do, any voice, any noise I can make has been used. Even Karloff, I had never done it on The Simpsons and then this past Halloween episode we did a Lugosi-Karloff sort of take-off, so I ended up using Karloff for The Simpsons. He didn't lisp as much as I made him lisp though."

I asked him whether any particular accents had eluded him – Irish in particular: "I can do a bit of Irish but it's not very good. I appeared on Paul O'Grady yesterday, and couldn't understand a word he was saying." I had to remind Hank that Paul is actually from Liverpool!

I asked him whether his grip on The Simpsons had given him the power and clout in Hollywood to pick and choose his projects and he quite candidly told me: "Absolutely. It's now so much money, to put it bluntly, that I don't have to do anything else, which is fantastic. It's not like I'm offered everything under the sun but I can pick and choose what I'd like to do, which is great."

The Simpsons has extraordinary longevity and I finished up by asking him how much longer it will run: "We're in the middle of recording our 21st year, we'll definitely record through season 22, I know that, and we're contracted at least to do one more year."

He actually only works six hours per week on the show for his huge salary!