Mark Ruffalo celebrated National Selfie Day by bringing the Science Bros together once again on the set of Avengers: Infinity War. Unlike the lunchtime photo where Robert Downey Jr. and Mark Ruffalo were flanked by Doctor Strange stars Benedict Cumberbatch and Benedict Wong, this image features these scientific heroes sharing a moment together between takes on the Infinity War set. Given the massive size and scope of Avengers: Infinity War, it remains unclear how many actual Science Bro moments fans will get,

This photo from Mark Ruffalo's Instagram doesn't show either of the actor's costumes, but we can see a large blue screen behind them. Naturally, this blue screen could be used for anything, and Mark Ruffalo didn't offer any more details about what's going on behind the Science Bros in this photo. It's been more than two years since we last saw Mark Ruffalo's not-so-jolly Green Giant on the big screen, when he stole a QuinJet and took off for parts unknown at the end of Avengers: Age of Ultron. Thankfully, we'll get to see Hulk on the big screen later this year in Thor: Ragnarok.

RELATED: Avengers: Infinity War Concept Video Offers a Head-Turning New Look at Thanos

While many fans have been clamoring for a Planet Hulk adaptation, Thor: Ragnarok may be the closest that we'll get to that story being told on the big screen. We know that Thor will be exiled from Asgard and taken to a gladiator planet, where the reigning champion is in fact the Hulk. Mark Ruffalo teased in an interview last January that the Hulk story arc will connect both Thor: Rangarok and Infinity War, although what that connection may be is uncertain. Thor: Ragnarok is said to center on an "intergalactic road trip" with Thor and Hulk, who have never been the best of friends throughout their Avengers tenure.

There have also been rumors that Avengers: Infinity War may have a connection to the 2008 Phase 3 movie The Incredible Hulk, with actress Liv Tyler reportedly reprising her role as Betty Ross for this movie. Still, since Marvel hasn't confirmed any cast members or character for Avengers: Infinity War yet, all we have are rumors to go on. Marvel did bring back Betty Ross' father, General Thaddeus "Thunderbolt" Ross (William Hurt) back into the fold in last year's Captain America: Civil War, so it's certainly possible that his daughter may also return. If they both do come back, they'll be part of an ensemble that the Russo brothers revealed had as many as 67 characters.

We also showed you another photo earlier today featuring the Doctor Strange Sanctum Sanctorum, featuring the Russo Brothers and Doctor Strange director Scott Derrickson. While no details were given with that photo, the more we see from this epic adventure, the more fans will start to piece together, but as of now, there is very little to go on, with no official synopsis and no full cast list, although we have seen several stars on the set through recent set photos. Marvel hasn't confirmed when production will wrap on Avengers: Infinity War, but that may happen soon, since filming has been under way for nearly six months. Take a look at this Science Bros photo from Avengers: Infinity War below.