During filming, Montgomery Clift called Marlon Brando a slob and commented that he was using only about one third of his talent.
According to TCM, this was Dean Martin's 2nd film after his break with long-time partner Jerry Lewis, perhaps more significantly, it was his first dramatic film role. Martin connected with co-star Montgomery Clift, they became friends, and Clift, one of the most respected actors of his generation helped Martin with his role. They ran lines together, and then during the party sequence when he sensed Martin was nervous, Clift hid under the piano and began tickling Martin's leg, until he had a laughing fit, it was all done to loosen Martin up. Martin nicknamed Clift, Spider, because of the extravagant gestures Clift would make when he talked.
Dean Martin was a close friend of Montgomery Clift. Martin was always grateful for the help Clift had given him while filming "The Young Lions (1958)," Martin's first major dramatic role, and he would accompany him to parties after the rest of Hollywood had disowned him due to his increasing addictions to drugs and alcohol.