Working alongside Sacha Baron Cohen on The Dictator provided Sir Ben Kingsley with a unique acting challenge – keeping a straight face. Sir Ben admits that there were plenty of occasions while filming on location in Spain and New York when he was on the verge of breaking down in hysterical laughter.

“Fortunately, I was the straight man,” he says.  “I wouldn’t dare to try and be funny around Sacha Baron Cohen, because that’s more than my job’s worth."

“And I loved being his straight man, but it was very challenging—there were things going on right in front of my face that were screamingly funny and all I was allowed to do was look a little bit baffled."

“It was hilarious, and to be two inches away from Sacha going at full blast and to have to be stoically indifferent to what he was doing was the most challenging acting exercise I could imagine.”

The two men first met when they worked on Martin Scorsese’s charming, critically acclaimed children’s adventure story, Hugo, although each had been aware of the other’s work for years.

“I first became aware of Sacha when I watched his Ali G television show (in the UK).  I remember howling with laughter at the opening credits and then those outrageous interviews he did.  I thought it was one of the funniest things I’d ever seen.

“I worked with Sacha on Hugo and I didn’t waste any time telling him how much I admired him when we chatted on the set.  We only shared a tiny scene together at the end of Hugo when, I rescue the boy from him, but we were on the set together and I watched him work.  We built a nice relationship.

“And then he phoned me and sent me the original script for The Dictator, from which we strayed very little, actually.  And he said, ‘Look, we are working in a very precise, scientific way, in that we construct a scene almost from the ground up.

“Would you come over to New York to work with Larry and me, and discuss the script and see how we all get on?’  And I had the most marvelous afternoon with Sacha, Larry and Scott Rudin, the producer, where we just dove into it and improvised.  It was great fun.”

In The Dictator, Baron Cohen plays General Aladeen (the ruler of a fictional North African state, Wadiya), who is determined to resist any attempts to bring democracy to the country he has oppressed for decades.

When The Dictator arrives in America to address the United Nations amid growing concerns that he has been illegally developing nuclear weapons, events back in his homeland threaten to lead to his overthrow.

“My character is called Tamir, who is the general’s uncle, and my official title is Minister of Security and Procurer of Women,” laughs Sir Ben.  “So I would be handing out the Rolexes and the dirty diamonds, as well as looking after General Aladeen’s security.

“The General goes to New York for a UN meeting, and things start to happen back in his own country while he is away.  Also, while he is in New York, there’s a mix-up and they don’t realize who he is.

“And also, rather like [in Charles Chaplin’s] The Great Dictator, there’s a twin, a double.  It’s like in [the film] Dave, where there were two presidents - there’s a double and there’s a huge amount of comedy mileage that comes from that.  And I have to look after the double.”

Baron Cohen is a fearless performer, says Sir Ben, and a master of comedy satire.  He compares him with the late great Charlie Chaplin.

“Sacha is as fearless as Charlie Chaplin was when Chaplin decided to make the film The Great Dictator, which was in 1940.  I recently got a DVD of it and I was amazed that it was made so early in the war.  Before the US had entered the war, he was making jokes at Hitler’s expense, and Nazi Germany and fascist Italy.

“It’s a mercilessly funny film and a great piece of satire and dangerously timely.  And the only parallel with Sacha that I can imagine would be walking on to the set with Charlie Chaplin, who was making those movies before I was born.”

It is a huge compliment.  “Well, it’s from the heart.  And as I say being two inches from the guy when he is going full blast is amazing.  When you work with somebody like Sacha, it raises your game and it’s very, very exciting.

“And also it was a pleasure to work with his lovely leading lady, Anna Faris, and all the great cast that he had gathered around him.  It was marvelous.”