Watch Dean Martin: King of Cool for Free: How to Stream the Movie Online at 123Movies. . Dean Martin had a laid-back charm that made him successful in everything from big-screen comedies to television variety shows to live acts in Las Vegas. Filmmaker Tom Donahue explores Martin’s varied career, including his complicated relationships with Jerry Lewis, Frank Sinatra, Sammy Davis Jr, and others. We hear from admirers such as critic Gerald Early, actor Jon Hamm, and Hip-Hop artist RZA who testify to Martin’s enduring mystique.