Joe and Anthony Russo dropped a new public tease on Instagram on Friday — a single green square with the caption "something's brewing" that also tagged Robert Downey Jr., Marvel Studios, Avengers, AGBO Films and SXSW London.
The image is why people are searching for Avengers Doomsday now: the Russos are due on a panel at South by Southwest London next week, and the tag list points directly at an event that could be used to kick off the next round of promotion for the film.
The timing stacks. AGBO was announced in April 2026 as a major partner for SXSW London, the Russos are in post‑production on Avengers: Doomsday, and the festival runs June 1 to June 6 — the brothers’ slot is the short panel titled "Deadline Live Studio: CLOSE UP - AGBO," hosted by Donald Mustard and scheduled from 2:15–2:30 BT.
That combination of name tags and timing is the clearest evidence yet that new marketing may be imminent. The Russos’ post literally says, in their words, "something's brewing." They have a platform, a partner and a public invitation on the calendar; the film itself remains set to open in theaters on December 18.
Still, the tease lands against a notably sparse public campaign. Doomsday has had only four small teasers and a CinemaCon trailer shown in 2026 that was not released publicly; it has been about four and a half months since the fourth trailer turned up in theaters with Avatar: Fire and Ash. Crucially, no publicly released footage has shown Robert Downey Jr. as Doctor Doom, even though Downey will lead a cast of dozens in the film.
That gap — a high‑profile lead whose Doctor Doom has not yet been seen in public footage — is what converts a vague green square into a potential reveal. If the Russos intend to move the marketing needle, showing Downey, a new trailer, or both at SXSW London would do it. The Russos have delivered major franchise moments before: they directed four prior Marvel films together, and Doomsday is their fifth movie with the franchise.
There is an unavoidable contradiction in the post itself. It hints at something immediate, while the public record shows marketing that has been quietly constrained so far. The CinemaCon material demonstrates that there is footage to show; the Russos’ tagging of SXSW and AGBO — the studio partner announced in April — signals where they might choose to put that footage on a public stage.
Given those facts, the most likely next move is clear: expect the Russos to use their SXSW London panel to unveil tangible marketing — whether a new trailer, an exclusive clip, or the first public glimpse of Downey in Doctor Doom. The green square is not a promise, but the tag list, the festival partnership and the brothers' post‑production status make a public reveal at the June 1–6 event the logical conclusion.
