But this Christmas, with the release of the final adventure of Bilbo Baggins, he'll finally say goodbye to Tolkien. Is he relieved? Disappointed?
"Well, it has been such an enormous part of my life for the past 14 years. And not just Middle-earth, but my relationship with New Zealand. Not that that will end, as I plan to go back there and make more films. So I don't really see it as coming to an end."
Surely they're not further raiding the Tolkien hobbit-hole and making The Silmarillion next? "P'raps not," he chuckles, his London accent coming to the fore. "P'raps I'll shift around that one."
Is he a mo-cap character in Star Wars? "I ... he begins, ... can't answer that."
Is he human? "I can't answer that."
Is he made of metal? "I can't answer that. I'd love to be able to tell you," he insists, seemingly sincerely. But of course he can't. JJ Abrams' production of Episode VII, currently bunkered at Pinewood Studios outside London, is a black hole of character and plot information.
Like the rest of the cast - from Game of Thrones' Gwendoline Christie to Girls' Adam Driver, from Carrie Fisher to Mark Hamill - Serkis has been sworn to secrecy on pain of Jedi death. But how about another tack...
Did he see Harrison Ford fracture his leg on the door of the Millennium Falcon?
"No, I didn't," he replies with a sympathetic wince. "Poor guy. But apparently he's been - pardon the pun - a real trouper. He wants to get back on set as quickly as possible and get on with it."
Still, every cloud and all that: fanboys and fangirls the world over must surely have been rejoicing that the Millennium Falcon being used on set is sturdy enough to break bone. It's clearly not balsa-wood flimsy nor CGI smoke-and-mirrors. It's not even mo-cap trickery. It's a proper, Rebel-shuttling, hunk of old-school spacecraft.
"Yeah, if you're gonna get hospitalised, that's the way to do it," Serkis laughs. "But that's the one thing that's possibly safe to say: JJ is absolutely, 100 per cent honouring the original three movies. It's filled with the love and sensibility of those films."
Is he related to Boba Fett?
"I can probably safely say that I'm not related to Boba Fett," he smiles.
Damn, the Force is strong with this one.
The Independent