Recording his dialogue for Portal 2 was one of the most exhausting jobs Stephen Merchant has ever taken on, so says The Office co-creator.
There may be spoilers ahead.
Merchant told MTV that the process of trying to embody the role of robotic sphere Wheatley was a physically gruelling process.
"I'm in this little recording booth, shouting down these imaginary corridors, imaginary gantries, pretending to fall off things and really trying to move around and live it as best I could," he recalled.
"I know it sounds really pretentious, but really try to move around like this robot so my voice would feel like it was animated.
"I was really working hard to try and put myself in that environment, I guess, which is not something I normally do as a performer," he admitted. "Normally I just rock up and I do the lines and I go away again. I'm not an accomplished actor. But for some reason I was really working hard."
He added that the experience initially put him off the idea of potentially reprising the role in any future Portal games.
"When I finished it I was like, I can never do this again, I'm so tired. Honestly, I'm not just exaggerating for the interview. I was really tired.
"By the third or fourth session, I was not looking forward to it. I was just like, I'm gonna be exhausted after this. So, at the time, I was thinking, Oh, I don't fancy doing this again."
However, the positive reaction he's had since the game's release last month has given him a new perspective.
"What I was really pleased by how people seemed to respond to it in the way they do with a movie they've enjoyed, or a TV show they've enjoyed. They seemed to respond to it as entertainment.
"It never occurred to me that people would respond to it in the way they do with other stuff I've done. I felt like, 'Oh, actually this is a really legitimate, creative art form now.'"
Alas, Merchant didn't have any intel on what the future might hold for Wheatley, not to mention the series in general.
"I'm a robot, I don't need to die. They could bring me back anyway if they wanted. Make it a prequel!"
Portal 2 snagged a perfect 10/10 from Eurogamer last month, with Oli Welsh singling out Merchant's performance for praise.
"Merchant's prattle might chafe with some players, but I loved his deflating, humanising effect on Portal's cold brilliance."
Check out the trailer below for a quick taste of Merchant in action.