The 65-year-old frontman with The Heavy metal group is notoriously set in his ways, and filmmakers Wes Orshoski and Greg Olliver said that while he was an incredible subject for them to make a documentary about - he could be hard to persuade to do even basic shots.
Greg told BANG Showbiz: "He was very conscious the whole time of not looking like an asshole. Not looking like a reality TV star."
Wes added: "One of the funny fights we had with him for a long time was we needed a shot of him walking down the sidewalk from his apartment.
"He was like, 'You gotta call the BBC, they already filmed that'. We were like 'ha ha ha, sure' but he was like, 'No, seriously - I already did that'.
We were like, 'Well we need it for our movie', he was like, 'Well, I'm not doing it'.
"He'd never do anything at all even as simple as that for us. Then one day he was like, 'Guys I'm going to walk out of The Apartment in a second'.
"We jumped up and ran to the car to get our equipment, we were there fighting over it and us tripping over each other on the sidewalk like paparazzi to get the shot.
"But it looks great in the movie - he's smoking in slow motion."
The pair of directors added they had little plan when they started to plan the film the bass player's everyday life, other than they wanted to create an "honest portrait" of the 'Overkill' rocker.
Wes added: "We certainly wanted to make an honest portrait of him, we didn't have an agenda or an angle, we just wanted to follow him around and let him tell his story as he is and show him as he is. And I think he could see the sincerity in us doing that too."
'Lemmy' is released in UK cinemas from December 3 and will be out on DVD from January 24.