Playing a young ape nearly killed him. Well, from a physical point of view, at least.
But that hasn’t stopped Andy Serkis blazing a trail in his role as Caesar, the leader of the genetically enhanced primates who have survived to remind humans how to be, well, human again.
Serkis, 53, returns for the third chapter of the rebooted sci-fi franchise, which began in 2011 with Rise Of The Planet Of The Apes and continued three years later with Dawn Of The Planet Of The Apes.
In the latest instalment, War For The Planet Of The Apes, the apes are still co-existing alongside the humans who’ve also survived the storm of Simian Flu.
Twelve years have passed since the virus, ALZ-113, changed the face of humanity and Caesar (Andy Serkis), his wife Cornelia (Judy Greer) and their children - Blue Eyes (Max Lloyd-Jones) and Cornelius (Devyn Dalton) - are living in exile in the woods with the rest of the apes.
Tranquillity is a short-lived luxury as one tragic event will trigger a showdown of epic proportions between the apes and humans.
For some stars, pinning their flags to the mast of one franchise for such a long time would be a burden, but not for Serkis.
“Look,” he says frankly, “it’s so rare that you get an opportunity as an actor to play a character all the way from birth through to late maturity, over the course of three movies. It’s a real luxury.”
But the actor, who has continued to blaze a trail in motion capture since his 2001 performance as Gollum in The Lord of The Rings saga, has also found this storyline to be the most challenging of them all.
“In the respect that Caesar has been this empathetic leader who is trying to find peace between apes and humans and suddenly all of that is turned on its head when the events that happen at the beginning of the movie throw him wildly off course and he turns into this revengeful killer,” he says, adding: “This one has been hugely taxing - in a good way.”
At the centre of a storm of human evil lies one of the film’s new characters, Colonel McCullough, played by Woody Harrelson.
The Natural Born Killers star is not the only new recruit as fans of the franchise will meet Nova, a mute orphan (played by Amiah Miller) and the character Bad Ape, played by Steve Zahn.
For Serkis, switching back into ape mode is both the known and the unknown.
“It’s interesting because on the one hand I feel like I know it well - I do know Caesar very well, but as the films have progressed he is changing, evolving, from a chimpanzee that we see right at the beginning of Rise, through to an evolving ape who is also in charge of creating a society in Dawn, to this almost human-like character in War where he is beginning to speak more like a human,” he says.
And, of course, there’s the physicality of it all which sees the actors who play apes mimicking their body language and posture to the closest degree.
Through performance capture it’s all translated digitally on to the big screen.
Luckily for Serkis in this film, Caesar is now an adult, meaning less time spent hobbled over as a youthful ape. “Yeah, that was the one good thing about this one,” he recalls.
“Actually, the most difficult part of Caesar’s life was portraying him when he was young, when he was literally a young chimpanzee, and that physically nearly killed me.
“But as he’s got older, he’s my age basically, he has become more upright. Still in this movie, you’ll see Caesar quadrupedal-ling fast to run away from things, but actually in essence he’s more upright, which is fine by me.”
For director Matt Reeves, who also helmed 2014’s Dawn Of The Planet Of The Apes, this film is a perfect oxymoron of intimately grand.
“I feel like it’s both grander but also more intimate,” Reeves says.
“I feel like a war story really only matters if what’s going on in the intimate foreground you’re engaged with, right. So the war is between the species, but the war that matters the most is the war that’s within the characters and specifically the war that is within Caesar.”
The question is: who wins this war?
War For The Planet Of The Apes is in cinemas now.