Marvel's upcoming blockbuster movie, Avengers: Infinity Wars, will feature all the Earth's mightiest heroes uniting to fight the villain, Thanos, and according to Marvel comic book artist/writer Jim Starlin, the movie will not disappoint fans.

Starlin shared some tidbits from his recent visit to the set of the Avengers: Infinity War sequel, aka Avengers 4, which is currently filming in Atlanta, Georgia. Starlin seems pleased with what the Russo Brothers are doing with Mad Titan Thanos, who will make his proper debut in 2018's Infinity War.

He wrote on Facebook, "I wanted to take a few days before commenting on my visit to the Avengers: The Infinity War set; giving myself time to consider what exactly I should and could say about the trip."

He continued, "I want to tell all you Thanos fans out there, without giving anything away, you're not going to be disappointed, far from it. I truly believe folks will be pleasantly shocked by how delightfully different these two movies will be from previous Marvel films.

A post shared by The Russo Brothers (@therussobrothers) on

Starlin concluded his post by praising the directors, Russo brothers. "Joe, Anthony, Chris, Stephen and the rest of the gang have my complete confidence in their ushering of our favourite Mad Titan out from the world of comics and into the Marvel cinematic universe. My first born leaves the nest to wreak havoc on the heavens. What more could a proud father hope for?"

Meanwhile, fans are still wondering when the first trailer will drop for Infinity Wars. As we already know, trailer footage was shown at the 2017 Comic-Con San Diego and was briefly leaked online. All we know for sure is that the trailer will come out by the end of the year.

A new fan theory on Reddit has come up with a "formula" for the release of Avengers franchise trailers.

According to the theory, judging by the film release dates of Marvel's The Avengers and Avengers: Age of Ultron and when the first trailers for those films were released (both came out in October), the user predicted that the first look at Avengers: Infinity War may air sometime this next week, or the end of October.

However, Marvel is yet to confirm the trailer release date and we urge fans to take the news with a pinch of salt, Avengers: Infinity War will be released in theatres on 4 May, 2018.