Russell, you were asked to star in this film then you brought Helen on board. How did that come about?

RB: Well when it’s a remake, people start assuming you’re going to replace John Gielgud with a bloke – who will you get, Michael Gambon, Anthony Hopkins? As soon as I said, “I’ll get a woman”, there was obviously only one choice. And the whole movie opened up once you imagined Helen in that role. As an actor it gave me much more interesting things to play in my relationship with a mother figure.

Helen, did you jump at the chance?

HM: Well I kind of jumped, but with terrible trepidation. Mostly because it was Russell! [Russell shouts, “The nerve of you, woman!”] We had worked on The Tempest together but never really spent any time together until this. Russell is quite an intimidating person, because he’s so brilliant and extraordinary and rock’n’roll and I feel so boring and ordinary next to him. So it was quite scary. And I’m not very good at edgy, modern comedy. But in the film meeting I saw this incredibly bright and interesting person making this thing happen – and I fell in love.

Russell, what was your first impression of Helen?

RB: Well with people you’ve been aware of your whole life – you know the cultural real estate that Helen occupies… Agitator of the male; Oscar winner; sexy; there’s a lot of… baggage seems pejorative, but, there’s a big reputation. I felt daunted, but the heartening thing is when you meet heroic people often you find they’re able to be ordinary. Helen grew up in Essex and me and all my old mates who work with me still are from Essex, so we all got on wonderfully. Helen is very gentle and fun to be around. And then working, one of the things I find with her – I haven’t worked with loads of brilliant actors, Helen’s the most notable – but we’d be doing a scene and I’d think [does huffy voice], “Pah, she ain’t doing much, I’m carrying this,” and then you’d see it on the monitor, and go, “F***ing hell! That looks so much better on the screen!” There is stuff that they know, people like Helen. It’s not fair.

Did Russell change into character as soon as the director called action, or was he just playing himself?

HM: No, he was just him. But I think he found a character that’s not really Russell because Russell is not really childish.

Or spoilt, or rich...

HM: Well, he’s quite spoilt. And quite rich actually. He found this delightful childlike quality in Arthur, when he is very grown-up. I haven’t seen the movie, but if it works, it’s because of that. You could as an audience go, “Oh f**k off you spoilt t**t, get out of my face,” so you have to be charming. So I think that’s what Russell did.

RB: I remember growing up not having money and there’s a resentment towards people that do. But I once went to Oxford University and the students were so lovely that I thought it was beautiful that they had such a lovely institution. I didn’t feel a sense of resentment or that we should smash down this gorgeous university and build mess halls for the proletariat. Nobility is a trait as well as a class of people. So there’s a sense that Arthur is decent, that he has some humanity.

Helen, was Russell just ad-libbing on set? Because some of his lines sound like classic Russell Brand lines.

HM: Of course they are. Almost all of them are! Some of the most genius improvisations – watching him on set you just went, jaw drop, oh, my, god. He just goes off and he’s so unbelievably brilliant and wise and smart. His best one was this rant about what it means to be English.

RB: Nations are like human beings – when you’re absent from them you start to recognise what is beautiful about them. English people, the music of The Smiths, West Ham United, walking down a Camden street and people shouting “Awright” at you out of vans. Here they shout “Hey get him to the Greek!” People always shout.

Russell, you’ve played Aldous Snow in Forgetting Sarah Marshall and Get Him To The Greek, and now Arthur, both louche out-of-control characters who get drunk and seduce women. They seem reminiscent of your old life. Would it be harder to play somebody sober like you are now?

RB: Well I don’t know but this is what I think about: Aldous Snow was meant to be an author but they liked me so they made him more rock’n’roll, and then they liked him so much they gave him his own movie, so that’s really just one incident prolonged into two movies. And Arthur is a pre-existing piece of material. For me it’s no more typecasting than seeing Clint Eastwood with a gun. There are certain facets of people’s nature that play off. For me it’s no more difficult to say “I have a problem with alcohol” than “We’re having some problem with livestock down on the farm.”

The Queen and the Jester