It's hard to imagine anyone other than Bruce Willis playing John McClane, but he wasn't the first choice. However, "choice" isn't exactly the right word, as 20th Century Fox was forced to offer the Die Hard role to Frank Sinatra, who was 70 years old at the time. Die Hard is based on a novel called Nothing Lasts Forever, and that novel is a sequel to The Detective. Sinatra starred in the 1968 adaptation of The Detective, and his contract stated that he had the right to reprise his role in the event of the franchise continuing. While Die Hard isn't a sequel to The Detective, the contract still applied.