(Updates with confirmation, adds details, byline, quote) By Ian Ransom MELBOURNE, March 26 (Reuters) - Harry Kewell, Australia's first world-class footballer, will call time on his 18-year career at the end of the A-League season next month, the 35-year-old said on Wednesday. The Sydney-born former Leeds United, Liverpool and Galatasaray forward signed a one-year deal with Melbourne Heart in a bid to play in a third World Cup finals, but has spent much of the 2013-14 season sidelined by injury. "My last game will be on the 12th of April at AAMI Park against my home town, Western Sydney Wanderers." Voted Australia's greatest ever footballer by fans in 2012, Kewell won 56 caps and scored 17 goals for his country. More...