It seems hard to imagine, but in the early 1970s tennis was not only the fastest growing participant sport in America, it was also one of the most popular, on par with football and baseball and more popular than basketball. The popularity of tennis grew to such an extent that pro-am tournaments popped up all over the country, allowing spectators to watch matches involving professional tennis stars and celebrities alike. Bill Cosby, Charlton Heston, Ed Ames, and many others were regulars at these events, and were deemed very good players. Vince Van Patten was so good he turned pro for a while.
One of the best Hollywood star tennis players, and one of the most identified with this new celebrity tennis, was James Franciscus, who was among the top ranked celebrity players for years. Franciscus was an early adopter of the sport. As early as 1963 he can be seen in an episode of Mr. Novak, in which the blue collar teacher schools some bluebloods at their own sport.
An episode of Mr. Novak in which Franciscus shows his tennis skills.
Franciscus also played a professional tennis player in a movie in the 1970s - Puzzle, an Australian action-adventure flick.
More than just an early adopter, Franciscus was also a passionate advocate for the sport, and in 1970 he founded the James Franciscus Celebrity Tennis Tournament to help raise money for multiple sclerosis research (a disease that had afflicted his mother).