Citadel, which is being screened on streaming giant Amazon Prime, stars Indian actress Priyanka Chopra Jonas who has repeatedly backed Meghan publicly.
Ms Chopra Jonas, 41, plays the leading lady, an elite espionage agent Nadia Sinh in the five-part spy action series.
And in the third episode, she is involved in a scene with a crime boss named Balduino Basto, portrayed by Sen Monro.
Richard Madden's character Mason Kane goes to see Basto in Morocco under Nadia's instructions and she is speaking to him in his ear.
Basto is then asked for help to break into the armed forces chief's office.
It prompts him to say: 'The chief of armed forces? You might as well have asked me how to get between the legs of the Duchess of Cambridge!'
It comes after it was last week claimed that the new live action remake of Disney movie The Little Mermaid, which is one of the Duchess of Sussex's favourites, contains a dig at her sister-in-law.
A critic who saw an early screening of the film noted the apparent jibe against the Princess of Wales, in the script for the movie.
The reviewer pointed to the scene where Ariel and Prince Eric meet, after she's given up her voice to get to the surface and he has to try to guess her name.
He said: 'His first guess is Diana. His second guess is Catherine, but after [Ariel gives a disgusted] reaction, he [concludes] 'OK, definitely not Catherine.'
'Disney would be disingenuous to imply those name choices were coincidental.'
Citadel is one of the most expensive television shows, with a production budget of almost £300 million. It premiered on April 28 and a second season has recently been commisioned.