Last week, it was confirmed that production started on Marvel's highly-anticipated Avengers: Infinity War, which is currently filming in Atlanta. Directors Anthony Russo and Joe Russo shared the first set photo on Facebook, while Sean Gunn shared a photo of his own, as he arrived on the Atlanta set and revealed the movie's new logo, which was on a winter hat. Today we have another set photo that reveals a new cast member wearing that same Avengers: Infinity War hat, Pom Klementieff, which confirms that the Guardians of the Galaxy 2 star will return in Avengers: Infinity War as Mantis.

Pom Klementieff debuted the new photo on Instagram, which was preceded by another photo of an Avengers comic book which revealed the origins of her Mantis character. The actress will make her MCU debut as Mantis in Guardians of the Galaxy Vol. 2, which kicks off the summer movie season on May 5. It has already been confirmed that the Guardians of the Galaxy will all return in Avengers: Infinity War, but this new photo was the first confirmation that Mantis is joining the fight as well. Naturally, we don't know how large role a role Mantis will have in Avengers: Infinity War, but she's just the latest addition to an already massive cast.

Back in December, a casting call revealed an extensive cast list, which included Josh Brolin (Thanos), Chris Hemsworth (Thor), Sebastian Stan (Bucky/Winter Soldier), Scarlett Johansson (Natasha Romanoff/Black Widow), Jeremy Renner (Clint Barton/Hawkeye), Chris Evans (Captain America/Steve Rogers), Elizabeth Olsen (Wanda Maximoff/Scarlet Witch), Samuel L. Jackson (Nick Fury), Paul Rudd (Scott Lang/Ant-Man), Paul Bettany (Vision), Chadwick Boseman (T'Challa/Black Panther), Mark Ruffalo (Bruce Banner/Hulk) and Robert Downey Jr. (Tony Stark/Iron Man). It also confirmed that Brie Larson's Carol Danvers/Captain Marvel will be part of the action, following the confirmation of the actress taking on that role at Comic-Con. It was also confirmed that Doctor Strange stars Benedict Cumberbatch and Benedict Wong will return as Stephen Strange and Wong.

RELATED: Disney+ Announces Missing Marvel & Star Wars Movie Release Dates

Earlier this month, Tom Holland also confirmed that he will return as Spider-Man in Avengers: Infinity War, while the first new cast member was announced, Game of Thrones star Peter Dinklage. While his character has yet to be confirmed, there have been some theories that he's playing MODOK and Pip the Troll. Last week, the actor was spotted in New York City, getting his hair dyed red, which strengthens the theory that he's playing Pip the Troll, but we still don't have confirmation from the studio yet.

Pip was a Laxidazian alien who became physically and psychologically mutated after he got drunk on a mutagenic hallucinogenic ale. He was cast away by his people and became an antagonist of Adam Warlock. Perhaps more importantly, Pip the Troll actually played a role in the Infinity Gauntlet comic book storyline, so there is reason to believe he could be used in the movie, since it is at least loosely based on that story. Deadpool creator Rob Liefeld was one of the biggest proponents of this theory that Peter Dinklage would be playing Pip, revealing his take on the theory on Twitter shortly after the news broke. Take a look at Pom Klementieff's set photos from Avengers: Infinity War as production continues.