The original Iron Man trio of Robert Downey Jr., Gwyneth Paltrow, and Jon Favreau are reuniting once again for a Marvel film - and Marvel Studios is publicizing the reunion. Take a look:
The trio were together in the final moments of Spider-Man: Homecoming, so it looks like the happy reunion will continue on to Avengers: Infinity War.
Another interesting note is the chest apparatus Downey Jr. is wearing behind the scarf. A previous set photo showed Downey wearing a shirt with a circle cut out, so this could be the return of an arc reactor (or something close) on Tony Stark.
The tweet bills this as part of Avengers: Infinity War despite the untitled Avengers 4 currently being filmed. Director Joe Russo has said, however, that they would be going back to film some additional Infinity War scenes during the fourth film's shooting.
Avengers: Infinity War is scheduled to be released May 4, 2018.