From August to October 1972, Lee began work on his fourth Golden Harvest film "Game of Death". He began filming some scenes, including his fight sequence with American basketball star Kareem Abdul-Jabbar, a former student. Production stopped in November 1972 when Warner Brothers offered Lee the opportunity to star in "Enter the Dragon", the first film to be produced jointly by Concord, Golden Harvest, and Warner Bros. Filming began in Hong Kong in February 1973 and was completed in April 1973. One month into the filming, another production company, Starseas Motion Pictures, promoted Bruce Lee as a leading actor in "Fist of Unicorn", although he had merely agreed to choreograph the fight sequences in the film as a favour to his long-time friend Unicorn Chan. Lee planned to sue the production company, but retained his friendship with Chan. However, only a few months after the completion of "Enter the Dragon", and six days before its July 26, 1973 release, Lee died. "Enter the Dragon" would go on to become one of the year's highest-grossing films and cement Lee as a martial arts legend. It was made for US$850,000 in 1973 (equivalent to $4 million adjusted for inflation as of 2007). "Enter the Dragon" went on to gross an estimated worldwide. The film sparked a brief fad in martial arts, epitomised in songs such as "Kung Fu Fighting" and some TV shows.