Mark Ruffalo is at it again, as he jokes the cryptic Avengers 4 wrap photo tweeted on Friday by the film's directors reveals a spoiler.The sequel to Avengers: Infinity War completed reshoots last week in Atlanta ahead of its May release. It's been an emotional time, with Chris Evans bidding an emotional farewell to the Marvel Cinematic Universe, but after directors Joe and Anthony Russo shared a photo to mark the end of production, Ruffalo couldn't help but make a joke.RELATED: Purported Avengers 4 Trailer Description Surfaces OnlineIn the wake of his recent exchange with the Russo brothers over his legendary tendency to reveal spoilers, Ruffalo pounced on the photo, responding, "... and you fired me for a measly slip of the title? Spoiler alert!"

The Russos recently teased that Ruffalo was fired after he pretended to spoil the title of Avengers 4 during an appearance on The Tonight Show Starring Jimmy Fallon.

It's well-established that some of the MCU's stars are a little loose-lipped. Tom Holland may have dropped the odd spoiler, but Ruffalo takes the crown after he accidentally live-streamed the start of Thor: Ragnarok and inadvertently ruined the end of Avengers: Infinity War in 2017. Whatever the Russo brothers mean with the blue blur, at least Ruffalo and the directors can see the funny side of spoilers.

As it stands, the cryptic image has fandom talking. With theories from Adam Warlock's return to Captain America's coffin making the rounds, the tweet may not become clear until Avengers 4 hits theaters. At the moment, the most popular guess is that the wrap photo is a tease of the movie's logo, and will finally give Avengers 4 its official title.

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Although reshoots have only just wrapped, the Russo brothers are already well into the editing process, leaving audiences waiting for the first tease of Avengers 4. Still, the directors are remaining tight-lipped on everything from the movie's title to which actors return, meaning May can't come soon enough.

Directed by Joe and Anthony Russo, Avengers 4 stars Robert Downey Jr., Chris Evans, Chris Hemsworth, Brie Larson, Mark Ruffalo, Jeremy Renner, Scarlett Johansson, Paul Bettany, Anthony Mackie, Paul Rudd, Elizabeth Olsen, Tom Holland, Benedict Cumberbatch, Chadwick Boseman, Chris Pratt, Zoe Saldana, Dave Bautista, Bradley Cooper, Vin Diesel, Karen Gillan, Evangeline Lilly, and Josh Brolin. The film arrives May 3, 2019.