Serkis brought life to Gollum during the five years spent making the Lord of the Rings trilogy. "Performance capture is one of the greatest actors' tools of the 21st century because it allows us the ability to transform into another character with limitless possibilities," says Serkis, speaking from his north London home. "As an actor you can play anything, and that's why the last 17 years have gone in this amazing direction for me." If Gollum, executed by New Zealand's ground-breaking Weta Workshop, was the beginning of the movement towards motion-capture acting, the Planet of the Apes movies has been its culmination. Serkis has played Caesar, whose scientifically-enhanced intelligence makes him a simian revolutionary, as a young chimpanzee in 2011's Rise of the Planet of the Apes, a brave warrior in 2014's Dawn of the Planet of the Apes, and now a conflicted, ageing commander in War for the Planet of the Apes, which opens on Thursday. To play the apes, Serkis and his co-stars have repeatedly gone through what they call "ape camp", an extended preparation where they spend long hours sitting on their haunches – by now Serkis can hold a squat for far longer than you – and getting used to the arm extensions that simulate their characters' long upper limbs. Serkis can climb, eat and run as an ape would, but he can also deliver lines and convey deeply held emotion. "It's incredibly freeing. What you don't get is any stimulation from the character or their costume, because you don't have those things," he says. "You have to bring the character to life internally, but you totally forget what you're working with after about five minutes, even if we were shooting War during a Canadian winter."

Andy Serkis plays the ape leader Caesar in the Planet of the Apes trilogy. Credit:Twentieth Century Fox The standard outfit for a motion-capture performance is a Lycra bodysuit, which along with his face is studded with markers to create a three-dimensional record of every movement through a tiny helmet-mounted tracking device that sits in front of Serkis' face. In production stills, at first glance he looks like a cyclist who's had parts of his bike grafted onto his body, but in War for the Planet of the Apes, Serkis and director Matt Reeves capture every nuance of Caesar's journey. "That was always Matt Reeves' intention – he's a brilliant storyteller and a great actor's director. When he stepped into this world to make Dawn, it was because he wanted to see the world through apes' eyes," Serkis says. "What he loved about the original film was the fact that it was so associated with Caesar. The film is called War for the Planet of the Apes, but it's also a war for Caesar's soul." Serkis and his co-stars in the Planet of the Apes films went through 'ape camp', spending hours sitting on their haunches and learning to mimic the movements of the creatures. Credit:Twentieth Century Fox With the latter films set in a post-apocalyptic world where a virus has killed billions and ended society, each instalment has dug deeper into Caesar's choices. The thrill of escaping a barbaric testing facility in the original Rise has been tempered by political rivalries and difficult decisions. But it is Caesar's adversary in War, Woody Harrelson's brutal soldier "The Colonel", who reveals humanity's depths.

"We are in a very precarious position worldwide because our ability to empathise with each other is diminishing. This film is about the perils of allowing that to happen, of objectifying other cultures and different species and not respecting the differences between them," Serkis says. "It's in the DNA of these films to be social commentary without being overly topical." Despite the visual effects in many of his major roles, Serkis says the 'characters would not have the life they have if they weren't authored by a live-action performance by an actor'. Credit:AP Photo/Scout Tufankjian The success of War, which has already topped the American box office upon week of release, has also reignited calls for Serkis' performance to be recognised during Hollywood's awards seasons. Industry guilds, which set the parameters for the likes of the Academy Awards, have previously failed to include motion-capture work alongside traditional acting performances, with Serkis patiently setting out why they should. "The visual effects work is there for everyone to see and they're phenomenal, but those characters would not have the life they have if they weren't authored by a live-action performance by an actor with those in the moment decisions an actor makes," he says. "That level of emotional intricacy just wouldn't exist if it was put together by a committee of animators. That works brilliantly for animation, but not for live action filmmaking." Serkis was the man behind Captain Haddock in Steven Spielberg's The Adventures of Tintin: The Secret of the Unicorn. Credit:WETA / Paramount

It has taken time, but his colleagues are starting to agree with him. After the American actor Steve Zahn, whose role as a traumatised chimpanzee in War was his first motion-capture role, saw the finished film he sent Serkis a glowing email, marvelling at the feeling of seeing his acting matched to a different species. "He couldn't believe that everything he'd done was on the screen and how it pissed him off when people said to him, 'Do you do the voice of that ape?'," Serkis adds. "I was like: welcome to the last decade and a half of my life." Serkis embodied an eight-metre tall Kong in Peter Jackson's King Kong. Credit:UIP Serkis doesn't dwell on the annoyance that comes with people assuming his Caesar or his Gollum or his Captain Haddock in Steven Spielberg's The Adventures of Tintin: The Secret of the Unicorn (yes, that's Serkis too) is a digital creation he simply dubs over during post-production. Instead, he's busy with The Imaginarium Studio, a company he co-founded in 2011 to pursue motion-capture performances and beyond. "The Imaginarium is about where and how we'll tell stories in the future," Serkis says. "In 10 or 20 years' time, will it be a shared immersive experience or something that happens on an individual level?"

The success of War for the Planet of the Apes has reignited calls for Serkis' performance to be recognised during Hollywood's awards seasons. Credit:Kent Blecynden/Dominion Post The husband and father of three, who still regularly gives live action performances in films such as Marvel's coming Black Panther, has also branched out into directing. This year there's the release of the intimate drama Breathe, a true story of physical fortitude starring Andrew Garfield (Hacksaw Ridge) and Claire Foy (The Crown), while next year brings a version of The Jungle Book where the motion-capture performers include Cate Blanchett, Christian Bale and Benedict Cumberbatch. "My life has been radically altered on a number of occasions not by what I set out to do, but what lay next to it – I call it the adjacent possible," Serkis says happily. "You set off on a journey and find yourself on another trip." War for the Planet of the Apes opens in cinemas on July 27. The best motion-capture performances

If you remove Andy Serkis' benchmark performances, you certainly thin the ranks of great motion-capture work, but there remains a growing selection of skilful, transformative roles. Bill Nighy as Davy Jones (Pirates of the Caribbean: Dead Man's Chest, 2006): An early, encouraging example, where the extensive sea creature layers added to Nighy's supernatural pirate can't extinguish the dastardly vigour of his acting. Zoe Saldana as Neytiri (Avatar, 2009): James Cameron's billions-making hit, which is scheduled for three sequels next decade, was a breakthrough for the future Guardians of the Galaxy star, showcasing vivid emotion and physical feats. Mark Ruffalo as The Hulk (The Avengers, 2012): Ruffalo entered the Marvel Cinematic Universe as exiled scientist Bruce Banner, but when rage made him big, green and angry he brought a soulful regret to the Hulk's destructive wrath. Benedict Cumberbatch as Smaug (The Hobbit: The Desolation of Smaug, 2013): A telling example of a part – a vengeful dragon – that previously would have been digitally animated, but used motion-capture to add Cumberbatch's expressions and movements to his voice.

Lupita Nyong'o as Maz Kanata (Star Wars: The Force Awakens, 2015): The young 12 Years a Slave standout was able to capture the serene strength (and occasional annoyance) of a 1000-year-old alien without heavy prosthetics or other restrictions.