Joe Russo, who directed Avengers: Endgame with brother Anthony, acted as a stand-in for Thanos star Josh Brolin in scenes where Karen Gillan’s Nebula appeared opposite the Mad Titan, Gillan reveals. Because Brolin was unavailable during filming on Gillan’s scenes with Thanos, Russo played the villain in plainclothes, substituting for Brolin with a headpiece depicting Thanos’ face in cardboard, itself affixed to a large stick to help direct Gillan’s eyeline opposite the eight-foot-something Thanos. The experience was “surreal,” Gillan admits, but the Avengers: Infinity War and Endgame directing duo are ”incredible.”

“You know what I love? It’s a funny story about Joe Russo. So when we were filming Endgame, we didn’t have Josh Brolin there for my scenes with Thanos, so Joe played Thanos,” Gillan said with a laugh at Comic Con Paris. “It was funny to sort of be in the scene, acting with one of the directors of the movie, and he was just wearing his own clothes, and then he had a stick with a big Thanos cardboard picture sticking into the air so that I would look at the right height. I was like, ‘This is surreal.’”

Endgame also gave Gillan the opportunity to act opposite of herself: when Tony Stark (Robert Downey Jr.) cracked time travel, allowing the Avengers to return to precise moments in the past to retrieve the six Infinity Stones needed to reverse Thanos’ snap that erased half of all life in the universe, 2023 Nebula confronted her past self from 2014’s Guardians of the Galaxy.

“I really liked it because the old, the past version of Nebula, represented where the character started off in the first Guardians of the Galaxy,” Gillan said. “She was very mean and evil, and then I got to interact with the future, the new Nebula, and it really showed the evolution of the character in one scene, which I really liked.”

The blue-skinned cyborg, who ultimately mended her relationship with sister Gamora (Zoe Saldana) before joining the Guardians, is “a really fun character,” added Gillan, who next reprises the role in the James Gunn-directed Guardians of the Galaxy Vol. 3.

“She’s a sadist, the biggest sadist in the galaxy,” Gillan said. “So she loves to hurt people and inflict pain on other people, but underneath that, is a broken, hurt, bitter girl who suffered an abusive relationship with her father.”

Marvel Studios has yet to announce a release date for Guardians of the Galaxy Vol. 3.

Upcoming Marvel Studios projects include Black Widow on May 1, 2020, The Falcon and The Winter Soldier in Fall 2020, The Eternals on November 6, 2020, Shang-Chi and the Legend of the Ten Rings on February 12, 2021, WandaVision in Spring 2021, Loki in Spring 2021, Doctor Strange in the Multiverse of Madness on May 7, 2021, Spider-Man 3 on July 16, 2021, What If…? in Summer 2021, Hawkeye in Fall 2021, Thor: Love and Thunder on November 5, 2021 and Black Panther 2 on May 6, 2022. Marvel Studios Disney+ series without release dates include Ms. Marvel, Moon Knight and She-Hulk.