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 CinemaBlend.com: "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."