Andre Kirk Agassi ( /ˈɑːndreɪ ˈæɡəsi/; born April 29, 1970) is a retired American professional tennis player and former world no. 1. Generally considered by critics and fellow players to be one of the greatest tennis players of all time, Agassi has been called the best service returner in the history of the game. Described by the BBC upon his retirement as "perhaps the biggest worldwide star in the sport's history", Agassi's performances, along with his unorthodox apparel and attitude, have seen him cited as one of the most charismatic players in the history of the game, and credited for helping revive the popularity of tennis during the 1990s.