The film is director Matthew Vaughn's third instalment of the "Kingsman" spy action films.
This outing is a prequel movie starring Fiennes.
Set in the early 20th century, "The King's Man" tells the story of how the independent intelligence Kingsman agency is created to defeat a devastating war plot.
It follows 2014's "Kingsman: The Secret Service" and 2017's "Kingsman: The Golden Circle", both set in the present day and starring Colin Firth and Taron Egerton as gentlemen spies.
Based on the comic book "The Secret Service", the movie, also stars "Byzantium" actress Gemma Arterton and "Notting Hill" star Rhys Ifans as Rasputin.
Actor Charles Dance, Disney's Executive Chairman Bob Iger, and actor Harris Dickinson also attended Monday's premiere.
"The King's Man" begins its global cinema roll-out on Dec. 22.