Actor Samuel L. Jackson revealed a trade secret from Bruce Willis that the actor says kept him sane during his five-decade career in Hollywood. Speaking to Vanity Fair earlier this week, Jackson said his “Die Hard With a Vengeance” co-star had a surprising reason for returning to the role of John McClane throughout his career.

It’s not hard to see exactly this play out in the careers of many stars. Bruce Willis himself returned to John McClain two more times after Die Hard with a Vengeance. He certainly had critical and commercial successes outside of the Die Hard franchise, but there were also plenty of films that failed to find an audience.