Walked out on first wife Pati Behrs and their family in 1955 for a pre-fame Ursula Andress, who had recently immigrated to the U.S. from Italy and spoke almost no English at the time. Behrs threatened to bring a morals charge against Derek for contributing to the delinquency of a minor, which could've meant deportation for Andress.

[on the interview with Cecil B. DeMille that led to his being cast in DeMille's final film] He was disappointed in my stature. He wanted me for the part of Joshua, the stonecutter, in The Ten Commandments (1956). He had studied me for months and knew more about me than I knew about myself. I was so used to being rushed through interviews that I stumbled over my words for the first fifteen minutes to get out everything I wanted to say. An hour and a half later I was still in there with him. A burning desire to play Joshua and a new enthusiasm for acting actually filled me. Finally, I told him that by the time he was ready to shoot, I would build up my body by scaling it down from one hundred eighty-five pounds to the proportions he wanted by weight lifting and I would be the best Joshua he could find.