It's always a tough call when an actor must play a part everybody thinks they know. There will always be the complaints: "Oh, he doesn't have the right ears" or "The voice is all wrong" and etc.
However Frank Langella, as the late US President Richard Nixon, is almost more Nixon than Nixon, and Michael Sheen, as the ubiquitous TV personality David Frost, even had Sir David Frost quaking in his boots when he went to the film's premiere in London.
Neither Sheen nor Langella are impersonators. Both are very fine actors and the way they tell the story of the interviewer Frost and his legendary television confrontation in 1977 with Nixon, the disgraced American president, is breathtaking. These interviews revolutionised the art of the confessional interview, changed the face of politics forever, and transfixed millions and millions of viewers world-wide.
The movie, directed by Ron Howard from Peter Morgan's play of the same name, which ran to huge success in both London and New York, is an electrifying tale of the two men's televised encounters that led to Nixon finally admitting wrongdoing in the Watergate scandal. Theirs was an intellectually gladiatorial contest, which only one could win.
But how did the two actors tackle getting under the skins of these two men, among the most famous faces of their time? "I tried to get into Nixon's pain more than anything else," Langella says in his lovely, rich, precise voice.
"His torment, agony, the deeply, profoundly human insecurities. He was as dimensional a human being as I could present. I wasn't interested in all the political footage on Nixon, I wanted to touch the man. I wanted Nixon's internal humanity on display." Certainly Langella, 68, makes Nixon if not likeable, then empathetic.
At the time Nixon and Frost meet, both men are slightly washed up. Nixon is exiled from public life, can't even do after-dinner speeches any more, and needs the $600,000 Frost was offering. Frost's bright young TV interviewing star is on the wane, can't even get the backing for the interviews, and had to stump up his own cash. Both are seeking rehabilitation, both have rampaging egos, both are showmen at heart and they are heading for a titanic clash.
"I had acted in the play in both London and New York," continues Langella, who is essentially a stage actor but in recent years has appeared in films such as Superman Returns and Dave. His next film is The Box with Cameron Diaz. "Originally, none of me responded to the play – I took the job as an opportunity to investigate the sort of person I'd never played before. There was no make-up, no tricks, just Nixon to portray, as goofy as he'd been portrayed over the years. It was a challenge that paid off. Nixon brought me many rewards.
"To get the look we tried different noses, wigs, teeth, eyes and ended up using just a tiny prosthetic at the end of my nose and joining my eyebrows a bit, and new teeth, not caps." He tells how one of Nixon's grandchildren who saw the play thanked him for making his grandfather human: "He said I had caught his look completely, a larger-than-life politician with a sort of air of mystery.
"It's funny, when I was young movie stars looked like Paul Newman or Clark Gable. Now we go for off-beat movie stars. The glamorous era is over. Now politicians like Obama have that glamour. Politicians like Churchill, Stalin, Roosevelt were larger-than-life politicians, mysterious giants. Now politicians all go on talk shows or play musical instruments or go on cooking shows. I'd personally like my president to have a bit of mystery with a real desire to be a great statesman. After all, he's supposed to be leading the nation."
Where, I ask, was he when the Frost/Nixon interviews were transmitted in America?
"I was in Williamstown, Mass, sitting on the floor in a little rented house romancing a girl and we watched it live on TV. Nobody who wasn't an adult can understand what an event it was. We were all against the Vietnam War, against President Nixon, it was a very painful time in America."
Michael Sheen, 40 this month, has been critically acclaimed for his chameleon abilities. We recently saw him as Tony Blair in The Queen, now David Frost and will next be Manchester United soccer manager Brian Clough in The Damned United.
He was born in England in the late 60s and didn't watch the Frost/Nixon interviews on television. But growing up in the 1970s he recalls that David Frost was the first huge television star presenter.
"He was one of the most powerful people in the country, from highbrow to through-the-keyhole," says Sheen in a deep base voice that changes remarkably to suit his real-life screen characters. "He was like part of the furniture, part of the household. He has a very good business brain and he managed to crossover and bring serious politics into popular arenas, into our sitting-rooms via TV. Frost is someone who was born to be on TV. Frost and Nixon lived their lives on TV. They were both people in the public eye. They liked to be liked.
"All my characters – Blair twice, Frost, Brian Clough – are showmen, all people in the public eye and hugely different between their public and private persona.
"When I've played real-life roles I need to get to the point when I'm not outside a character but inside him. I get it from the way someone speaks and watch out for the little clues. I look for the anomalies, the contradictions and store them away in my head."