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“They exist in parallel universes,” “Fantastic Four” producers Simon Kinberg and Hutch Parker told the Daily News in a joint email.

“The Fantastic 4 live in a world without mutants. And the X-Men live in a world without the Fantastic 4.”

“Crossing them over would be challenging,” said Kinberg and Parker, “but we sure would love to see all those actors together, the way we had them on stage at (San Diego) Comic Con.”

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