Sir Patrick Stewart thinks Bryan Singer is "looking for power".
The 78-year-old actor has worked with the director - who was fired from 'Bohemian Rhapsody' in December 2017 and has denied accusations of sexual misconduct - on five 'X-Men' movies and believes the "horrible" filmmaker seeks out "control over other people".
Speaking of the director in an interview with the Daily Telegraph newspaper, the 'Star Trek' actor said: "This sense of...looking for power, when you've already got it and you don't actually need it... Looking for control over other people, who you can dominate - it's horrible."
Rami Malek recently admitted working with Bryan on 'Bohemian Rhapsody' was "not pleasant" and it has been claimed the director would often be absent from set, and Patrick confirmed he had experienced similar issues shooting with the 53-year-old filmmaker.
Patrick continued: "I've experienced that too with him. There have been problems in the past."
When asked if Bryan would often be absent on key days, Patrick continued: "Yeah. Or turning up and not shooting.
"It was very difficult. We got through that. He's such a talented individual in the would of making movies - and, it would appear, extremely untalented and cruel in other respects.
"And it makes me profoundly sad for potential victims, or possible victims, as well as Bryan himself.
"Most of the experience with Bryan I really enjoyed. But what is happening is so good."
Bryan was fired from 'Bohemian Rhapsody' and replaced by Dexter Fletcher, however, still has the directing credit on the film.
Speaking of the director, Rami, 37, previously said: "In my situation with Bryan, it was not pleasant, not at all. And that's about what I can say about it at this point.
"For anyone who is seeking any solace in all of this, Bryan Singer was fired. Bryan Singer was fired, I don't think that was something anyone saw coming but I think that had to happen and it did."