With only nine days until Avengers: Endgame releases to cinemas worldwide, the anticipation for the end of Marvel Studios’ Phase Three is at fever pitch.While fans are lapping up every potential leak or new piece of information, Mark Ruffalo offered an endearing look at how Chris Evans and Scarlett Johansson, two of the Marvel Cinematic Universe's biggest stars spent, kicked back by taking each other on in Tetris with a pair of original Game Boys and the Game Boy Link Cable.RELATED: Avengers: Endgame's Paul Rudd Reveals His Take on the "Thanus Theory"

Fans responded to the image with joy and enthusiasm. The image has received almost 60,000 retweets and over 340,000 likes at time of writing. The comments on the thread were filled with GIFs of Evans and Johansson’s positive energy and how happy the wholesome image made them feel. One fan even went so far as to edit the image to transform it into a retro advertisement for the Game Boy itself.

It was only when the official Tetris Twitter account responded to the thread that the mystery of which game they were playing was solved. Evans and Johansson were doing battle in two-player Tetris.

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In that version of the classic puzzle game, both players play their own game of Tetris, trying to clear their blocks as quickly as possible. If a player clears multiple lines on their own board, it will send blocks to fill up their opponent’s board, and the player who can survive the longest is the winner.

With only a few days until the film comes out, it'll only be a matter of time until Marvel fans see if Captain America and Black Widow have similar smiles once Avengers: Endgame is over.

Avengers: Endgame releases worldwide starting from April 24th. Release in the United States is on April 26th. The film is directed by Anthony and Joe Russo, and stars Robert Downey Jr., Chris Evans, Mark Ruffalo, Chris Hemsworth, Scarlett Johansson, Jeremy Renner, Don Cheadle, Paul Rudd, Brie Larson, Karen Gillan, Danai Gurira, Benedict Wong, Jon Favreau and Bradley Cooper, with Gwyneth Paltrow and Josh Brolin.