A reference to Doctor Doom is hiding in Fantastic Four's exceptional new marketing campaign – and I'm convinced we're getting a Robert Downey Jr. cameo soon

You may not have realized it, but Fantastic Four: First Steps has given a big hint to the inclusion of Doctor Doom in its own retro-futuristic universe – but you have to look extremely hard to find it.

As part of People magazine's Fantastic Four issue, a series of in-universe ads were created. Some, like Reed Richards' suit endorsement, would make Don Draper proud with its snappy Sixties copy, but offer nothing more than window-dressing instead of outright world-building.

An ad featuring Herbie, the robotic assistant of Marvel's First Family, goes one step further, however.

At the bottom of the leaflet outlining the 'home hero' and his many functions, there's an offer for a 30-day trial, complete with free 'Doom Detection' early-warning system. You probably know where this is going.

With this being the Fantastic Four, it should be pretty obvious that Doctor Doom is never too far away. But, as of yet, there's been no concrete talk of Robert Downey Jr.'s Marvel supervillain appearing in the Marvel Phase 6 movie.

Right now, the Latverian ruler is part of Avengers: Doomsday and Avengers: Secret Wars, but the in-universe reference here suggests he could very well be making a cameo in Fantastic Four in just a few weeks – or is at least a going concern for the residents of the Baxter Building and beyond. It would even back up a previous report that Doctor Doom would show up before the pair of Avengers films, though director Matt Shakman later denied he would appear in the film.

Fantastic Four, starring Pedro Pascal as Reed Richards, Vanessa Kirby as Sue Storm, Joseph Quinn as Johnny Storm, and Ebon Moss-Bachrach as Ben Grimm, hits cinemas on July 25. The upcoming Marvel movie sees the alternate-universe supergroup dealing with the impending threat of Galactus (Ralph Ineson).

Still playing catch-up on the MCU? Don't worry, it's not all Doom and gloom: head on over to the Marvel timeline and our guide on how to watch the Marvel movies in order for the full story.