Scott Derrickson left the 'Doctor Strange' sequel as he wanted to concentrate on directing 'The Black Phone'.

The 54-year-old filmmaker departed 'Doctor Strange in the Multiverse of Madness' last year as a result of "creative differences" with Marvel and screenwriter C. Robert Cargill – who also left the project – says he chose to focus on the upcoming horror.

Cargill told "It was creative differences. (Scott Derrickson) wanted to do one movie, and Marvel wanted to do another movie.

"So he sat there and said, 'Well s***, I've got this great script that I wrote with Cargill, and I'm really proud of it.'"

He continued: "We were actually going to go out to other directors for 'The Black Phone', and Scott was like, he called me up and said, 'Dude, I have to make this movie. It's gotta be my movie, I have to do this.'"

Cargill also explained how Scott – who was replaced behind the camera for the Marvel Cinematic Universe (MCU) film by Sam Raimi - was keen to helm a project that he had total control over.

The 45-year-old screenwriter recalled: "It came down to Scott, and Scott's like, 'Well, I can make this movie that I'm compromising what I wanted to do on, or I could make 'The Black Phone', and he goes, 'You know, I want to make a movie with Cargill. I'm gonna go make 'The Black Phone'.

"It was, as he said publically, it was a hard choice to leave 'Strange' behind; but it made it easier that he had a movie that he was looking forward to. And then the experience was so great that we're just are so proud and happy with what we made."