Jean Simmons was originally cast in the lead female acting role as Valerie Russell but the part eventually went to Dana Wynter.
A parachutist during World War II, Richard Todd actually took part in the invasion of Normandy on 6 June 1944.
Actress Dana Wynter (who plays Valerie Russell) picked this movie as her favorite of all her films, calling it "an unresolved love story".
Average Shot Length (ASL) = 13 seconds. Or 18 seconds if the battle sequence near the end is excluded.
For the D-Day landing, director Henry Koster used only eighty soldiers and two LCVPs (Higgins Boats aka Landing Craft, Vehicle, Personnel landing craft).
The film utilizes an oft-used storyline of the war movie genre which has two soldiers in love with the same girl.
The naval scenes were shot at the former Long Beach Naval Shipyard at Terminal Island (between the San Pedro district of Los Angeles and the city of Long Beach) whilst the beach landing was filmed at California's Point Dume, a promontory on the Malibu Coast of the Pacific Ocean.
This film's opening prologue states: "1944. Half a million men awaited the signal to cross the English Channel. For many it was to be the last day of their lives. It was D-DAY THE SIXTH OF JUNE."
This is one of few American movies that present a specifically British viewpoint. Major characters are British whilst military forces shown in action are Canadian.
This movie is based on the fictional 1955 romantic war novel, 'The Sixth of June' by Lionel Shapiro. Shapiro had been a World War II Canadian war correspondent for 'The Montreal Gazette'. He actually landed with the Canadian armed forces on D-Day for the the Allied invasion of Sicily, Salerno and Juno Beach. 'The Sixth of June' novel won the Governor General's Award for English Language Fiction.
This movie was originally going to be filmed in England but it ended up being filmed in California, USA, on location there and at the Fox Studio back-lot.
This movie's "Special Force Six" is a fictional military unit and did not actually exist.