Pakistan, July 27 -- Original X-Men stars excited longtime fans with the biggest Marvel Crossover yet.

More than 25 years after launching the franchise, several of its stars reunited at San Diego Comic-Con.

They all promoted their return in Marvel Studios' Avengers: Doomsday, marking a major milestone in the X-Men's integration into the Marvel Cinematic Universe.

Actors including James Marsden, Rebecca Romijn and Kelsey Grammer appeared together at Hall H, while Patrick Stewart, Ian McKellen and Alan Cumming, though absent from the panel, are still expected to reprise their iconic roles in the film.

The reunion marked a full-circle moment for Marvel fans. After decades of being separated from the Avengers because the X-Men film rights...