Former Ireland and Lions captain Paul O'Connell has been forced to retire from rugby with immediate effect.
Lock O'Connell quit international rugby after injuring a hamstring during a 2015 World Cup group game with France.
He signed a two-year contract with Toulon but never played for the French side after failing to regain fitness.
"It is with deep regret that I have decided to retire from professional rugby following medical advice," said O'Connell, 36.
"Since sustaining the injury at the World Cup I have been fully focused on returning to fitness and starting an exciting new chapter for both myself and my family in Toulon. Unfortunately this will no longer be possible."
|Paul O'Connell's career in stats|
|Age: 36||Test debut: Ireland v Wales at Lansdowne Road, Feb 3, 2002|
|Height: 6ft 6in (1.98m)||Weight: 17st 5lb (111.5kg)|
|Ireland caps: 108 (eight tries)||Captained Ireland to 2014 & 2015 Six Nations titles|
|British and Irish Lions caps: Seven||Key member of 2009 Grand Slam team|
O'Connell, who had a long domestic career with his home province of Munster during which he won two Heineken Cups, earned 108 caps for Ireland and seven caps for the British and Irish Lions.
He captained his country 28 times and also led the Lions in three Tests.
Fellow Ireland great Brian O'Driscoll said it was "really disappointing" to learn of O'Connell's retirement and described his former team-mate as "simply irreplaceable".
England head coach Eddie Jones said the lock was one of the greats of the game, while England back-rower James Haskell said O'Connell had the "respect of all the rugby fraternity".
O'Connell added: "I have been blessed to be a professional rugby player for over 14 years and to be part of Munster and Ireland teams that have experienced success.
"I have played with some of the best players to ever line out in the red of Munster and the green of Ireland and have had the privilege of captaining my country."
He thanked everyone who had supported him at Young Munster, Munster Rugby, the IRFU and Lions Rugby, adding "special thanks" must go to his wife, Emily, and to his parents, Michael and Shelagh.
"Lastly, I would like to thank everyone who has supported the teams I have been a part of," he said. "The support you have shown me is humbling and an immense source of pride for both myself and my family."