It's the movie that people still debate whether it qualifies as a Christmas film -- Die Hard. The popular action film franchise emerged with John McTiernan's 1988 film Die Hard, followed by some forgettable sequels. But the first film was so memorable that it was even selected for preservation in the National Film Registry in 2017.

Die Hard stars once lesser-known actors like Bruce Willis and Alan Rickman as John McClane and Hans Gruber, respectively. It's also credited for launching Willis' film career before his roles in '90s films like Armageddon and The Sixth Sense. However, one of the most recognizable voices of the 1940s had to be considered for John McClane before Willis entered the picture -- Frank Sinatra.

RELATED: Samaritan Looks Like the Spiritual Sequel to M. Night Shyamalan's Unbreakable

John Crawls Through The Vents In Die Hard

McTiernan's film was based on Roderick Thorp's 1979 novel Nothing Lasts Forever. However, 20 years before Die Hard's release, the 1968 film The Detective hit theaters. The crime film followed a police detective that had plenty full of marital issues and a complicated murder case on his plate. But The Detective was also based on Thorp's 1966 novel of the same name and starred one of the most popular singers at the time of its release.

Well-known entertainer Frank Sinatra was not recognized simply for his catchy anthems and his alleged connection to the Mafia. He also ventured into the film industry, including the lead role of Det. Sgt. Joe Leland in The Detective, alongside actors like Jacqueline Bisset and Robert Duvall. While Die Hard wasn't a direct sequel to The Detective, Nothing Lasts Forever was the book sequel to The Detective. So, even though Die Hard changed the lead character's name and several plot elements, producers were legally required to offer Ol' Blue Eyes the lead role of John McClane. But given that Sinatra was 70 years old, he obviously had to turn down the part.

RELATED: The Sopranos Is as Much About Mental Health as It Is About Crime

Frank Sinatra in The Detective.

Since Sinatra couldn't get involved, producers had to look elsewhere for their leading man. Willis wasn't immediately considered, as his acting portfolio included only the comedy-drama series Moonlighting. Action stars such as Arnold Schwarzenegger, Sylvester Stallone and even Clint Eastwood were prospective McClanes. And even when producers turned to Willis, he rejected Die Hard because of his commitment to Moonlighting.

Willis was only able to play McClane after his Moonlighting co-star Cybill Shepherd became pregnant, which led to a filming hiatus on the series. While Sinatra was physically incapable of starring in the lead role, it would have been special to see Ol' Blue Eyes make a Die Hard cameo. But despite not being the first choice, Willis has maintained the Die Hard legacy more than three decades after the first film's release.