Ten years ago, Marvel announced they were making their quirkiest film to date. With little known about the script and a cast of unknown actors on the call list, pressure rocketed. Critics panned the premise and casting, tipping it was likely to fail.
But when it was released in 2014, Guardians Of The Galaxy became the third-highest-grossing film of the year, taking in more than US$700 million at the box office.
For Chris Pratt, at the time best known for his work in US sitcom Parks And Recreation, says he was determined not to audition for the superhero film.
It was "partly because I had been rejected so many times" in other films of the same genre, but also because he was carving out a new path for himself, in both a personal and professional sense.
"In the summers [in between Parks And Recreation], I would be doing critically acclaimed movies, while also physically changing my body to play a Navy SEAL in [thriller film] Zero Dark Thirty," Chris, 43, tells TV WEEK.
"I remember my mindset and self-perception shifting away from the guy who would likely be relegated to the funny, sweaty, fat, sidekick, to something more. I still wanted to do an action film and be funny, but just in my way."
With some convincing, Chris met director James Gunn, who was struggling to find the right actor to play Peter Quill.
"We wanted someone to breathe their own life into the role," James, 56, says. "I had easily read [auditioned] 200 people before Chris, and the actors didn't quite fit the character. He blew me away."
As they pair team up once more for the final instalment, both admit that they, along with the rest of the cast, shed a few tears.
Guardians of The Galaxy Vol.3 follows the misfit bunch – Quill, Nebula (Karen Gillan), Gamora (Zoe Saldaña), Drax (Dave Bautista), Groot (Vin Diesel), Mantis (Pom Klementieff) and Rocket (Bradley Cooper) – on a mission to not just defend humanity, but one of their own against evil threats that could tear them apart.
WATCH: Zoe Saldana: 25 Things You Don't Know About Me. Article continues after the video.
Karen Gillan says it wasn't easy to bring her character Nebula's arc to an end, one that has evolved through several sequels and Avengers spin-offs.
"I was in denial," Karen, 35, jokes of saying goodbye. "I've been with Nebula for nearly a decade and it's extraordinary to show different sides of her. It's been a fascinating exploration."
The Scottish actress experienced cult fandom before any of the others thanks to her breakout role in UK sci-fi favourite Doctor Who. She says youth [she won the role when she was 21] played a part in her "blind optimism". She had no idea what was coming.
"I was young and naive, so I thought lots of things came with that level of fandom, but I was more intimidated to join the Marvel universe; it was more removed from where I am from."
While it's goodbye to the guardians, it's unlikely it's farewell to each other. And perhaps not to Nebula.
"I could keep going with that forever!" Karen says, adding that the cast will never forget what they created.
"We've been through so much," she says. "None of us, apart from Zoe, had much of a film career, so we were all catapulted together. When you go through changes like that, it bonds you forever."