The actress, previously best known for starring alongside Matt Smith in Doctor Who, said she has been surprised by Nebula’s importance in the Marvel movies.
Now, it seems her involvement is only going to get more pivotal in Infinity War and its as-yet-untitled 2019 successor.
“I had no idea that this was where the character was going,” she told ScreenRant.
“I genuinely signed onto the role thinking it was eight days of filming and then I was going to die in the first Guardians [of the Galaxy].
“Three movies later and there’s three more to come out it’s, like, crazy.”
She added: “It’s funny because I read the Infinity Gauntlet, which is what the new Avengers films are based on, as research for my character because it’s her sort of biggest moment within the Marvel comic book world, and then to find out they’re making a double-bill feature based on that, I was just so excited actually because Nebula gets some really cool stuff.”
Anticipation is sky high for Infinity War, particularly after the latest trailer landed last week and sparked a wave of excitement – at time of writing it has over 36 million views on YouTube and 34 million on the Marvel Studios Facebook page.
But with several characters rumoured to be killed off in the blockbuster, it seems nobody is safe: Iron Man, Thor, Doctor Strange and Captain America all looked to be in particular trouble in this latest footage.
Thanos (Josh Brolin) will be seen collecting the Infinity Stones in the film, with the consequences unimaginable if he is successful.
The supervillain is the adoptive father of Nebula, as well as Gamora – played by Zoe Saldana.
Avengers: Infinity War is out on April 26 in the UK.