Marvel’s Avengers Doomsday is already setting itself up to be something of a direct sequel to Avengers Endgame.

Chris Evans’ return as Steve Rogers has already been revealed in the first teaser trailer, with the former Captain America at home in the 1940s with a baby he has with Peggy Carter.

Rumour has it that he didn’t return the Infinity Stones after all, which is causing multiverse madness.

Now fans will remember that the Fantastic Four rocket ship from Earth-828 was spotted orbiting Earth-616 by the New Avengers in the Thunderbolts* end credits scene, which you can view below.

And according to a new plot leak, Steve Rogers is riding it along with Marvel’s First Family and Robert Downey Jr’s villain.

According to reliable scooper MyTimeToShineHello: “In Avengers: Doomsday, Victor asks the Fantastic Four for help with the Incursions. They travel together with Steve Rogers to the MCU in their ship to warn everyone, then join forces to head to the X-Men universe – the source of the next Incursion that will destroy their Earths. They have a plan to fix everything.”

But why would Steve be with the Fantastic Four if he’s from Earth-616, the Sacred Timeline? Fans have some great theories below.