They seem to be from different generations, if you believe the characters in And When Did You Last See Your Father?. Yet Jim Broadbent is 11 years older than his on-screen son, Colin Firth.
"Jim's just one of those people who looks like he comes from another age," says the film's director Anand Tucker (Hilary & Jackie). "He's always been a character actor, but he's very good at it. He has to play both someone in their 40s and late 60s and manages to pull that off, which is no mean feat."
Based on Blake Morrison's 1993 biographical novel, the deceptively simple story taps into the fraught father-son relationships that seem to burden most men.
After being estranged for years, Blake returns home as his father, Arthur, is dying. While in a Hollywood movie they would kiss and make up, thankfully that doesn't happen here. While Firth bravely makes the son mostly unlikeable, viewers can't help but forgive Broadbent's lovable, self-absorbed father for all his shortcomings.
"The truth of Blake Morrison's situation was that he and his dad were really different kinds of people," says Tucker. "There's this kind of myth that sons are meant to be chips off the old block but that's quite different from the reality. There's no rule that says we have to get on.
"Arthur Morrison was a big, blustery, gregarious character, who overshadowed his son, and that was what we were trying to go for in the movie."
The story flits back and forth between the late 50s and mid-80s, to show Arthur in his prime, and also to demonstrate his son's resentment, which has festered down the years.
It all culminates in a resonant scene where Blake offers his father the opportunity to make amends as he lies close to death.
"Colin is trying to ask Jim if he would like to talk, and Jim says, dismissively, 'Oh, what do you want to talk about?' But Colin doesn't have the courage to say anything," Tucker says.
"It's a beautiful scene. We didn't rehearse it, we didn't talk about it, we just did it, and it all just fell into place for the two wonderful actors."
At 59, Broadbent is an actor with a natural sense of authority, whether playing mentor to Indiana Jones (even more of a stretch since Harrison Ford is 66) or Hogwart's new teacher Horace Slughorn in the upcoming Harry Potter and the Half-Blood Prince. At 47, Firth is more the leading man romancing the fairer sex, whether it be Meryl Streep in Mamma Mia!, Rupert Everett in drag in St Trinians, or most famously as Mr Darcy in Pride & Prejudice and the two Bridget Jones movies, where Broadbent played Bridget's father.
"It makes a huge difference that we knew each other so well," says Firth of working on their project. "We were able to get on with it."
The actors are vastly different people. Broadbent is a private man who rarely gives interviews. "He's shy," says Tucker. The dry-witted Firth is able to be hilarious about almost anything while at the same time having something of that buttoned-up Brit about him.
"They're both fantastic actors but they're also great guys, lovely men," says Tucker.
"The atmosphere on set was jovial and kind of blokey, but it was revelatory for me when they began to work.
"Colin likes to watch himself back on the monitor - he fine-tunes his performance very, very carefully - whereas Jim is all about instincts.
"He was pretty much doing the crossword until the moment we began to shoot and we pretty much got the shot in one or two takes and that would be it. Jim's instincts are absolutely phenomenal.
"He's so experienced now he trusts himself to go to the edge of the cliff and to see what happens," he says.
Who: Colin Firth and Jim Broadbent
What: And When Did You Last See Your Father?
When: Opens at cinemas on Thursday.