Rapper/actor Mos Def has signed on to star in “Something the Lord Made,” a true story based on a black lab technician and a white surgeon who were pioneers in heart surgery.Mos Def will star as Vivien Thomas, the real life assistant to Dr. Alfred Blalock, who will be played be Alan Rickman.Thomas was forced to leave his first year of college for lack of funds and went to work for Blalock in his laboratory.Blalock needed a surgical assistant and chose Thomas. Thomas learned to perform operations and remained invaluable to Blalock throughout his career.Thomas supervised the surgical laboratories at Johns Hopkins University for over 35 year. In 1976, he was awarded the honorary degree Doctor of Laws, by the Johns Hopkins University.The movie is slated to run on cable channel HBO.