Billie Jean is a tennis player.
Billie Jean King ( née Moffitt ; born November 22 , 1943 ) is an American former World No. 1 professional tennis player . In 1973 , at age 29 , she won the Battle of the Sexes tennis match against the 55-year-old Bobby Riggs , and was the founder of the Women 's Tennis Association , World TeamTennis ( with former husband Larry King ) , and the Women 's Sports Foundation . The WTA Finals ( formerly known as the WTA Tour Championships short : WTA Championships ) , is a professional tennis tournament played annually at the end of the season for the top-ranked players on the Women 's Tennis Association ( WTA ) tour .