20th Century Fox CEO Stacey Snider has warned studios against releasing too many superhero movies.

DC and Marvel have both enjoyed significant success with superhero franchises over the last decade, but Stacey has admitted that the studios are in danger of saturating the market with their films.

She explained: ''The studios need to have a bigger appetite for big cinematic, tentpole-type entertainment that isn't necessarily based on branded material.

''When you think about 'The Greatest Showman' ... what we had to hang onto was that the music was incredible and that, if ever there was a person to be 'The Greatest Showman' at Christmastime, it was Hugh Jackman. The same with 'The Martian' - it was based on a book that was self-published. It was hardly a bestseller.''

Stacey thinks it's important that the movie business broadens its horizons beyond superhero fans, especially as it's becoming an increasingly globalised industry.

She shared: ''If we don't continue to reach out to the folks that come more than just to see 'The Avengers,' we are going to have just the weekend business.''

The Fox chief admitted, too, that in a social media age, superhero movies are in danger of falling out of favour pretty quickly.

Stacey explained: ''[This] is a reality that we have all had to live with for the last several years.

''I think it is a result of a consumer who is more knowledgeable - they have more information about the quality of the films, they've got more choice, so they can opt in or opt out based on word of mouth and other recommendations.''

She also explained that superhero movies need to feature ''local diverse casts'', citing 'Deadpool' - which starred the likes of Ryan Reynolds and Zazie Beetz - to prove her point.

Stacey explained: ''When you look at a movie like 'Black Panther' or 'Coco', or in the case of 'Deadpool' - it is led by Ryan Reynolds, a Caucasian, but we have a diverse cast that surrounds him - I would venture to say that Zazie Beetz is as popular in the film as he is.

''We are mindful that these big franchise films need to be original, need to respond to local cultures, and local diverse casts.''