Last week, it was confirmed thatproduction startedon Marvel’s highly-anticipatedAvengers: Infinity War, which is currently filming in Atlanta. DirectorsAnthony RussoandJoe Russoshared the first set photo on Facebook, whileSean Gunnshared 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 sameAvengers: Infinity Warhat,Pom Klementieff, which confirms that theGuardians of the Galaxy 2star will return inAvengers: Infinity Waras Mantis.

Pom Klementieffdebuted the new photo onInstagram, which was preceded by another photo of anAvengerscomic book which revealed the origins of her Mantis character. The actress will make her MCU debut as Mantis inGuardians of the Galaxy Vol. 2, which kicks off the summer movie season on May 5. It has already been confirmed that theGuardians of the Galaxywill all return inAvengers: 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 inAvengers: Infinity War, but she’s just the latest addition to an already massive cast.

Back in December, acasting callrevealed an extensive cast list, which includedJosh 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) andRobert Downey Jr.(Tony Stark/Iron Man). It also confirmed thatBrie 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 thatDoctor StrangestarsBenedict CumberbatchandBenedict Wongwill return as Stephen Strange and Wong.

Earlier this month,Tom Hollandalso confirmed that he will return asSpider-ManinAvengers: Infinity War, while the first new cast member was announced,Game of ThronesstarPeter 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 theInfinity Gauntletcomic 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.DeadpoolcreatorRob Liefeldwas one of the biggest proponents of this theory thatPeter Dinklagewould be playing Pip, revealing his take on the theory on Twitter shortly after the news broke. Take a look atPom Klementieff’s set photos fromAvengers: Infinity Waras production continues.