Celebrity Birthdays, July 21

Happy Birthday to "Pearl Harbor" actor Josh Hartnett (1978), "The Last Starfighter" star Lance Guest (1960), "SNL" alum Jon Lovitz (1957), 80s singer Taco (1955), "RV" star Robin Williams (1951), expatriate singer Cat Stevens (1948), "The Andy Griffith Show" actor Don Knotts (1924; d. 2005), and author Ernest Hemingway (1899; d. 1961).