Australian rugby is mourning the death of former Wallabies lock Dan Vickerman at age 37.
Australian Rugby Union CEO Bill Pulver said the rugby world was in shock after the news.
The Union said Vickerman passed away at his family home in Sydney on Saturday night.
It is understood there were no suspicious circumstances. He leaves behind a wife and two young children.
The giant lock played 63 Tests for the Wallabies in an international Rugby career spanning a decade from 2002-2011.
His final Test appearance was the 2011 Rugby World Cup semi-final against New Zealand in Auckland.
Born in South Africa, Vickerman moved to Australia as a 21-year-old when he linked with the Brumbies and made his Super Rugby debut in the 2001 season.
He went on to play three World Cup tournaments for his adopted nation before injuries forced his retirement in 2012.
The All Blacks and former Wallabies team-mate Quade Cooper were among those who tweeted tributes to Vickerman.
"The shockwaves of his tragic passing will be felt right across our rugby community," Waratahs chief executive Andrew Hore said in a media release.
Former Australian flanker Phil Waugh played rugby with Vickerman at the Waratahs, and the Wallabies.
He said Vickerman was an influential figure in the Wallabies' 2003 rugby world cup campaign, in which they were runners-up.
"Vicks was heavily involved in that and he was very uncompromising in battle and you know just had such a huge physical presence, just a great guy you know to play alongside for so many years."
After three seasons and 33 appearances for the Brumbies, he was signed by the Waratahs in 2004 and played five seasons and 53 matches for them.
After playing in his second Rugby World Cup in 2007, he withdrew from Australian rugby for three years to study in England.
Vickerman earned a degree in Land Economics from Cambridge University and played in two Varsity matches whilst studying at the University, captaining the side to 31-27 victory over eternal rival Oxford in 2009.
The 204cm powerhouse then returned to Australia in time to earn selection by Wallabies coach Robbie Deans for the 2011 World Cup.
The union's Bill Pulver said Vickerman was an uncompromising competitor who forged a wonderful international Rugby career despite a number of injury setbacks.
"He was an enforcer on the field and a much-loved character off the field. He cared deeply about the game and the players, helping players transition into life after Rugby in his role with RUPA [players association] following his retirement.
"Our thoughts and prayers are with Dan's family at this extremely difficult time."
Players association CEO Ross Xenos said Vickerman was universally respected by his peers and the rugby community
"Since retiring, he was very generous in giving back to the game through coaching and voluntary roles supporting players' off-field development."
- ABC / AAP