Pom Klementieff

Klementieff at the 2018 Brussels Comic Con

Klementieff's first professional acting job was the French independent film Après lui (2007), portraying the stepdaughter of the protagonist played by Catherine Deneuve.[4] Filming for her scenes took three days. During one scene, Klementieff was supposed to push someone down a set of stairs but accidentally fell down the stairs herself, and director Gaël Morel kept that shot in the final film.

Her first leading role was in Loup (2009), a French film about a tribe of reindeer herders in the Siberian mountains. During filming, Klementieff stayed in a camp, hours from the nearest village, where temperatures dropped well below zero. During filming she befriended nomads who lived there, worked with real wolves, rode reindeer, and swam with a horse in a lake.[8]

Klementieff made her Hollywood debut in Spike Lee's Oldboy (2013), a remake of the South Korean film of the same name.[8][10] She portrayed Haeng-bok, the bodyguard of the antagonist played by Sharlto Copley. A fan of the original film, Klementieff heard about the part through Roy Lee, a producer with the remake, and took boxing lessons after learning the role involved martial arts. After showcasing her boxing skills during her audition, Lee asked her to go home and come back wearing a more feminine outfit and make-up, like her character in the film.[4][5] She contributed some of her own clothes to the character's wardrobe,[4] and trained three hours a day for two months for an on-screen fight with star Josh Brolin.[4][10] Klementieff came up with the name Haeng-bok, Korean for "happiness", herself after Lee asked her to research possible names for the character.[4][8]

Klementieff moved to Los Angeles after Oldboy was filmed and began pursuing more Hollywood auditions.[4][8] She continued taekwondo after the film, and has a purple belt as of the summer of 2014.[4] Her next acting role was the film Hacker's Game (2015), in which she plays a hacker she compared to Lisbeth Salander from the novel The Girl with the Dragon Tattoo. Klementieff used her boxing skills again in the film, and due to the movie's low budget, she had to do her own make-up and choose her own wardrobe.[8] It was her idea to dye her hair purple for the role, to which the directors first objected but later acquiesced.[4] In 2017, she appeared in the romance drama Newness and the black comedy-drama Ingrid Goes West.

Klementieff received worldwide recognition when she joined the Marvel Cinematic Universe as Mantis, appearing in the films Guardians of the Galaxy Vol. 2 (2017), Avengers: Infinity War (2018), and Avengers: Endgame (2019).[11] In 2019, she appeared in an episode of the Netflix science fiction anthology series Black Mirror, the thriller film Uncut Gems, and had voice roles in the animated supernatural comedy film The Addams Family. In 2020, she had a recurring role as Martel in the HBO science fiction series Westworld.