What could it be?
The sibling duo tweeted a cryptic teaser video with the date “07/19/19”, which happens to be the same day as their upcoming San Diego Comic-Con panel.
The mysterious clip features the date in bold yellow lettering while audio from a previous panel in which they treated the audience to Infinity War footage is heard playing in the background.
While the pair have already confirmed that they won’t be directing another Marvel movie at this stage in time, fans have suggested they could instead be making an announcement about the MCU’s Phase 4.
“They are going to be listing off the planned Phase 4 MCU movies just like they did for Phase 3 in 2014,” one fan predicted on Twitter.
Another said: “This is audio from the day they showed the first trailer for Infinity war at comic con. It’s a clear sign that they will be announcing the movies for phase 4 on July 19th.”
An official description of their Comic-Con panel explains: “For the Russo Brothers, Avengers: Endgame was the culmination of an unprecedented four-film, seven-year journey through the Marvel Cinematic Universe that has included some of the most iconic experiences in modern cinema.
“Come hear directors Joe and Anthony Russo reflect on Endgame and their epic road to it as they segue into life beyond Marvel with their new company, AGBO, which happens to include an exciting array of new and old creative friends. With their independent film studio, AGBO, the Russo Brothers aim to nurture talent and create best in class content while keeping creative control fully in the hands of the artists. This discussion will be moderated by Collider’s Editor-in-Chief Steven Weintraub.”