Culpeper in Kramer's comedy It's a Mad, Mad, Mad, Mad World (1963), a small but key part that he was able to complete in nine non-consecutive days. The film was released in November 1963. Tracy's name topped the list of performers, and the comedy became one of the highest-grossing American films of the year. As his health worsened, he had to cancel commitments to Cheyenne Autumn (1964) and The Cincinnati Kid (1965). Film offers continued to come, but Tracy did not work again until 1967 when he took the starring role in Kramer's Guess Who's Coming to Dinner (1967), Tracy's ninth and final film with Hepburn. Guess Who's Coming to Dinner explored the topic of interracial marriage, with Tracy playing a liberal-minded newspaper publisher whose values are challenged when his daughter wishes to marry a black man, played by Sidney Poitier. Tracy appeared happy to be working again, but he told journalists visiting the set that the movie would be his last for he would permanently retire after filming due to his health problems. To commence filming, Tracy had to be insured for the high premium of $71,000 if he died during filming; Hepburn and Kramer both put their salaries in escrow until Tracy completed his scenes. In poor health, Tracy could work for only two or three hours each day. He completed his last scene on May 24, 1967. Tracy died 17 days later from a heart attack on June 10. The film was released in December 1967, and although reviews were mixed, Curtis notes that "Tracy's performance was singled out for praise in nearly every instance." Brendan Gill of The New Yorker wrote that Tracy gave "a faultless and, under the circumstances, heartbreaking performance". The movie became Tracy's highest grossing picture. He received a posthumous nomination for Best Actor—his ninth—at the 40th Academy Awards, along with a Golden Globe Award nomination and a BAFTA win for Best Actor. Personal life Marriage and family Tracy met actress Louise Treadwell while they were both members of the Wood Players in White Plains, New York—the first stock company Tracy joined after graduating. The couple was engaged in May 1923, and married on September 10 of that year between the matinee and evening performances of his show. Their son, John Ten Broeck Tracy, was born in June 1924. When John was 10 months old, Louise discovered that the boy was deaf. She