Watch: Johnny Flynn discusses future of James Bond
The British star told Yahoo he's sure there are 'big conversations' being had about who will replace Daniel Craig in the role of 007.
Operation Mincemeat tells the true story of an audacious military operation during the Second World War.
Read more: Actors who could be the next James Bond
British intelligence officers planted a corpse — complete with fake documents and an intricate backstory — in order to dupe the Germans into believing Allied forces would attack via Greece instead of Sicily.
Fleming was working for the Naval Intelligence Division at the time and is believed to have suggested the initial idea that became Mincemeat in the famous "Trout Memo".
In the film, Fleming provides narration for the story and assists intelligence officer Ewen Montagu (Colin Firth) and flight lieutenant Charles Cholmondeley (Matthew Macfadyen) in planning the operation.
Flynn said there are very few recordings or photographs from Fleming's life prior to the publication of the first Bond adventure Casino Royale in 1953.
"There was a fun bit of bridge building and imagining of that person who became very famous and trying to consider who that person was as a young man," he said.
Flynn added: "For me, a lot of the clues actually lay in the Bond films and the Bond books. I feel like Bond is almost an idealised version of what Fleming was during the war."
The 39-year-old added: "He gave him the same rank and he's in intelligence and all that. I think you can imagine Bond as the kind of macho version of the slightly geekier person that Fleming actually was.
"It's really fun. He's there tapping away on his typewriter and feeding into the plot and coming up with some of the ideas, but he's not on the frontline.
"It was a really fun character to play, especially with all of the Bond nods and references in the film. I loved it."
There are numerous winks to famous Bond elements during Operation Mincemeat, including a scene in which Fleming pays a visit to the real-life Q-Branch and muses on the gadget potential of a wristwatch.
As for the big screen future of Bond himself, Flynn recently said he doesn't think he'd be ideally suited to taking on the role of the superspy.
His Operation Mincemeat co-star Jason Isaacs had no qualms though, suggesting Flynn as an ideal choice for the role but conceding it's a "minefield" to discuss who should replace Daniel Craig after No Time to Die.
Flynn added: "I think it's such a difficult topic because there's probably some big conversations and decisions to have about what sort of person that should be. I don't even want to go there because it feels like a poisoned chalice.
"I think it's not for me to say. I think Daniel Craig did a good job."
Operation Mincemeat will be released into UK cinemas from 15 April.
Watch: Trailer for Operation Mincemeat