Meghan, the wife of King Charles' second son Harry, was reportedly in talks to continue her return to acting with an appearance in the third series of the Guy Ritchie action comedy.
James told the Press Association in an interview with co-star Kaya Scodelario: "Those kind of big, spurious rumours, I mean, I had heard one that Harry was going to join."
"Harry Styles?" Scodelario said.
"No, the prince," James replied.
"We should just start making ones up," Scodelario added of co-star rumours.
"Shows how little I know; I thought he was telling the truth."
Meghan was reportedly in talks for a role in a possible third season, although the series has yet to be renewed, according to Deadline.
The duchess, who made her name before her marriage in the US legal drama Suits, recently acted for the first time in almost a decade in a cameo as herself in the comedy Close Personal Friends, starring Lily Collins and Brie Larson.
The Duke and Duchess of Sussex and their children, Prince Archie and Princess Lilibet, have returned to the UK to begin a new life after six years of living in the US.
The family is said to be settling in the UK for an "extended period" amid speculation about how long they will stay and where they will live.
James said The Gentlemen's second season, screening now on Netflix, would "delve deeper" into its characters.
"The reason for doing more, the only way to do more, was to go deeper and darker, and more complex, because otherwise it's a kind of repeat," he said.
The show follows Duke Eddie Horniman (James) as he unexpectedly inherits his late father's country estate - which is home to an underground cannabis empire.
It is a spin-off from Ritchie's blockbuster of the same name, which tells the story of a US drug lord looking to sell his cannabis empire in England.
A leading talent manager said directors and producers would "absolutely want to meet" Meghan if she returned to acting, saying he had "no doubt there would be interest in her".
"If Meghan decided tomorrow that she seriously wanted to act again, directors and producers would absolutely want to meet her and audition her," InterTalent Rights Group chairman Jonathan Shalit said.
"Would she automatically be handed every role she wanted? Of course not. Nobody is," Professor Shalit said.
"But would doors open? Absolutely."
11°C