The movie, due out next year – and still without an official title – will pick up after several Marvel favourites ended up dead.
While those killed by The Snap have been widely predicted to make a comeback, those who met their maker earlier on in Infinity War have been subject to less discussion.
But Benicio Del Toro – who plays The Collector – has hinted he will be back.
The Collector appeared to be wiped out by Thanos (Josh Brolin) as part of the hunt for the Soul Stone, although this was never made explicitly clear.
Appearing on The Late Show With Stephen Colbert last night, Del Toro was doing a skit in which he sat in silence and emoted without speaking.
Colbert asked: “You’re The Collector in Avengers 3. You appear to die, spoiler alert. Do you appear in Avengers 4? Just blink.”
As Del Toro pointedly blinked, Colbert concluded: “That’s verified!”
Del Toro does not have Avengers 4 listed on his IMDb page at present, and presumably his involvement in it is not confirmed by Marvel.
But the eccentric Collector would certainly be a welcome sight for fans of next year’s movie – which, according to the writers, is not yet finished.
Speaking on the Fat Man on Batman podcast, they said: “The status of Avengers 4 is that we shot it, but it’s not due for a while.
“There’s time for reshoots and fixing and we’re scrubbing through it.
“The Russo brothers [directors] have been in there [the editing room] for a few weeks now and the team’s getting together tomorrow.”
They added: “It’s disheartening to get off the one that’s all done, and get in a room and it’s just full of parts.
“You know? It’s like, ‘ah, s**t. It’s not done.’”
Del Toro is currently promoting Sicario: Day of the Soldado, which is out on June 29.