Marvel Cinematic Universe stalwarts Robert Downey Jr. and Mark Ruffalo, who plays Tony Stark/Iron Man and Bruce Banner/Hulk respectively, celebrate National Selfie day with a snap of the two of them on the set of Avengers: Infinity War. The actors, who are dubbed the "Science Bros" by the Marvel fandom due to their smart and geeky on-screen characters in the MCU films, are only two of the countless characters that will be converging on the third Avengers movie in an effort to stop super-villain, Thanos (Josh Brolin) in his quest to collect all six Infinity Stones.

Dubbed as the culmination of everything that has transpired in the MCU thus far, Infinity War will be bringing together all the main game players in the cinematic universe in a single movie. The idea is everything comic book fans' dreams are made of with possible interactions between characters who have never met before like Steve Rogers/Captain America (Chris Evans) and Drax the Destroyer (Dave Bautista) and Wong (Benedict Wong) and Scott Lang/Ant-Man (Paul Rudd). But for some reason, there is still some different excitement that comes from seeing old pals reunite like Tony and Bruce.

The selfie is courtesy of Ruffalo who posted it on his official Instagram account with the caption "#nationalselfie day. Science Bros Style. With the inimitable @robertdowneyjr." The two are clearly in the set of Infinity War with the unmissable blue screen seen in the background. The photo, however, is taken in extreme close-up which does not reveal much on the aesthetic of the set that they were working on that day.

The film - which is no longer shooting back-to-back with the yet-to-be-titled Avengers 4 - has started shooting since January and with a couple of months already in production, more and more MCU characters have been popping in Atlanta to do their scenes. Earlier on Wednesday, a photo of Downey Jr., Ruffalo and Doctor Strange himself, Benedict Cumberbatch and Wong also made the headlines when RDJ posted a snap of them - in their superhero garbs (minus Ruffalo, who was just sporting a normal shirt), enjoying lunch together.

What is interesting about these recent photos is the fact that Tony seems to be spending a lot of time with people outside of Cap's circle of friends. In the production kick-off announcement of the project in January, he appeared in the video with Peter Quill/Star-Lord (Chris Pratt) and Peter Parker/Spider-Man (Tom Holland) - the former having no association with the super soldier while the latter obviously on the tech genius' side. Following their rift in Captain America: Civil War, Tony and Steve have headed separate ways and the last time we officially saw Steve was when he was breaking out the rest of his team in the underground prison that they were jailed in. In the mid-credit scene, however, we found out that he and Bucky (Sebastian Stan) were taken in by T'Challa (Chadwick Boseman) in Wakanda.

It's definitely a daunting task to bring almost everyone together - give them their own highlights and present it in a way that it makes narrative sense (not to mention tie-in the 15 films that MCU has had in the last decade) in a single movie that will run for less than 3 hours. Avengers 3 is ambitious, to say the least, but Marvel has been doing this for almost 10 years. They started with a huge gamble with Iron Man and it paid off. The massive ensemble spectacle is helmed by The Russo Brothers (Joe and Anthony) and the screenplay was done by Markus McFeely and Stephen McFeely - the same team behind Capatain America - Winter Soldier and Civil War.  Given these, it is safe to say that there is a higher chance that Avengers: Infinity War will turn out to be a success than a failure.

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Source: Mark Ruffalo