"I don't have a crystal ball, I never really know what people are gonna do or say", he told Zavvi. "I teased the voice a little bit, but my motto is to never know what to expect and just be ready for anything.
"People are passionate, and you never know what it is they'll get passionate about. But I've seen the movie twice, and I think I landed on a pretty damn good voice".
The actor was speaking to Zavvi alongside his co-star, Charlie Day, as their animated blockbuster The Super Mario Bros. Movie is just days away from arriving in cinemas. The much-hyped movie from Illumination Studios (best known for the Despicable Me franchise) sees them voice Mario and Luigi as they journey to the Mushroom world to stop Bowser (Jack Black) from taking over.
It's more faithful to the source material than the 1993 film, the last time we saw the brothers on the big screen, but Pratt states that Mario's voice needed to change in order for the jump between mediums to truly work this time.
"Charles Martinet is iconic, he's made these characters what they have been so far for several decades, but we're still limited in understanding exactly who they are. We know their costumes and what they sound like, but not too much about them.
"In terms of creating this new version of the Mario voice, it was really essential that we come up with something that would be able to sustain a 90 minute story, create a character that's got a level of heroism and emotional vulnerability, so that you could care about the relationships in his life with him, his father and his brother.
"We had to really zero in on something that was grounded and a little bit more real. It's one of the limitations of making a movie versus making a video game: you need to carry a storyline, and it's a different task to voicing a video game character".
Day's motivation to sign up for the role of Luigi came during the pandemic. The It's Always Sunny In Philadelphia star was stuck at home with his son, and found himself passing the time playing Luigi's Mansion with him - making it a happy coincidence when he was offered the role in the Mario movie.
"The role was at the forefront of my mind. Plus, it's a nervous character, which is something I get offered consistently!
"I think the real challenge for my would be if someone said I had to play a brave guy like Dwayne Johnson - I don't know how to do that, but I do know how to move through the world with trepidation and fear just as well as anybo0dy."
But although this role seems to be exactly in Day's wheelhouse, it casts him against type in a very specific way, which turned out to be one of the main reasons why he said yes to the role.
"This is the first time I've been cast as the tall man, and I'm loving every second of it! We're gonna just start requesting I stand on seven apple boxes when I do movies.
"Even with an animated character, there's a little piece of me that's delighted I was chosen to be the taller guy. I mean this with absolutely no sarcasm, I'm really enjoying this experience".
Whilst the movie may be more faithful to its original source material than the last Mario movie, both actors are vocal that paying tribute to the Nintendo games counts for nothing if you don't buy into the relationship between the brothers - which here, is afforded more screen time than ever.
Pratt continued: "I think it's the heart of the movie, caring about these two characters and caring about their relationship. There's a very touching moment towards the end of the movie, without giving away spoilers, where these two brothers are reunited and you should feel something there.
"The success of the film is really predicated on whether or not you do feel something, and I feel very strongly that the relationship works, and that it's instrumental in making this a a successful movie."
Day added that this is the biggest change that needed to be taken into consideration when moving to a new medium.
He said: "I think when you're making a video game, you have to create a bunch of tasks that the player has to overcome. But in a movie, it can't just be about a bunch of tasks that the character has to overcome - you have to establish a reason for the audience to care, no matter whether it's Super Mario Bros. or Jaws.
"I think they did a great job saying okay, if you're going to make people want to sit down and watch Super Mario Bros. for 90 minutes, who are these two brothers? They establish their relationship, and their hopes and dreams, then add the various challenges on top of it."
With the game series having been a fixture on consoles for nearly 40 years, there's a lot of this world to condense into a single film, with much getting left out. However, eagle-eyed viewers will spot several Easter Eggs nodding to the franchise's history, with Pratt watching the movie a second time largely to soak them all up.
"The first time I saw the movie, I was just swept up in the story. I couldn't believe that this was the movie that we did, and in animation, you don't always know what you're going to get until you're watching the movie.
"And then I saw it a second time, and I was like, okay, now I'm going to sit back now that I know what the story is, and I'm gonna look for these Easter eggs. They're in every frame, even in just the composition of some shots and how they move from left to right, mirroring the gameplay of the original NES game.
"Then you get the punch out at the pizzeria and all these Easter Eggs in Brooklyn, and that's before you go to the Mushroom Kingdom and the Jungle Kingdom, and you see all these references hidden in each of the different worlds. As a fan, I'd love a list of them all to see what I've missed - and I'd encourage other people to see it twice as well!"
In short, whilst this may be a younger audience's introduction to the world of Mario, hardcore fans of the franchise should rest assured: this is still, first and foremost, one for the gamers.
The Super Mario Bros. Movie is released in UK cinemas on Wednesday, 5th April.
Read our interview with Seth Rogen, Jack Black and Keegan-Michael Key.
