Benedict Cumberbatch didn’t bathe and contracted nicotine poisoning during filming of ‘The Power of the Dog’

Method acting may be getting the best of Benedict Cumberbatch.

For his latest role in the new Western “The Power of the Dog,” the Academy Award-nominated actor went days without washing and ended up suffering nicotine poisoning.

Cumberbatch admitted he became one with his character, Phil Burbank, a 1920s Montana rancher who smoked like a chimney and rarely bathed his body.

“That was really hard,” he told Esquire of having to constantly smoke on camera. “Filterless rollies, just take after take after take.”

The vice took its toll on “The Imitation Game” star, who revealed he smoked so much he gave himself “nicotine poisoning three times.”

“When you have to smoke a lot, it genuinely is horrible,” he admitted.

Regarding hygiene care — or lack thereof — the 45-year-old London native (who also stars as Doctor Strange in the Marvel Cinematic Universe) confided: “I wanted that layer of stink on me. I wanted people in the room to know what I smelt like.”

“It was hard, though. It wasn’t just in rehearsals,” Cumberbatch continued. “I was going out to eat and meet friends of [director] Jane [Campion] and stuff. I was a bit embarrassed by the cleaner, in the place I was living.”

He was so entrenched in his character, he didn’t break the mold throughout the shoot and didn’t answer to his real name. “If someone forgot … and called me Benedict, I wouldn’t move.”