The idea of a crossover between "X-Men" and "Fantastic Four" is possible and the film franchise's director, Bryan Singer, says that there have been talks about it, ComicBook.com reports.

Previously, there had been rumors that an "X-Men" and "Fantastic Four" crossover could be happening in 2018 under the condition that "X-Men: Apocalypse" and the latter's reboot would make it big in the box office, but since "Fantastic Four" will be released under Fox, it seemed like a far-fetched idea.

However, during an interview with Yahoo UK to promote the "X-Men: Days of Future Past - The Rogue Cut," he said that there had been talks about a crossover between the two superhero films.

"Those ideas are in play," the director tells the media outlet. "That would be a natural match-up because they're both ensemble films." He further explains that there is a "natural mechanism" by which the crossover could be made, saying that it "deals with time."

However, even if the idea of a crossover is being discussed, Singer said that there are still certain conditions that have to be considered in order for it to actually happen.

"We have to see how the films turn out...to really understand what kind of desire and how that would really work," Singer says, according to Variety. "You have to see how the films evolve before you make the decision to complete commit to that."

Other than that, Singer would not divulge anything about the crossover, but it does give a clue as to what the director was referring to when he mentioned that the crossover would be possible through a natural mechanism which concerns time.

It is known to everyone that the plot of the "First Class" trilogy concerns itself with time travel, thus making the plot rather complicated, ScreenRant says. Other than the issue on time, it is still difficult to see what kind of reality the mutant characters of "X-Men" would hold in the world of "Fantastic Four."