Ulster and Ireland flanker Stephen Ferris has retired from the game at the age of 28 because of an ankle injury.
The Lions back-row was sidelined for 16 months after suffering the injury in a Pro12 game against Edinburgh.
Ferris made his comeback against the Scarlets in March but only managed three more games.
"I have had a great career, met many wonderful people and I hang up the boots with no regrets," said Ferris, who won 35 Ireland caps.
Ferris made his debut for Ulster as a substitute against Border Reivers in 2005 and was named Ulster's Player of the Year in 2006.
He represented Ireland at the 2011 Rugby World Cup in New Zealand and played in all five games in the 2009 Grand Slam success.
Ferris was selected for the British and Irish Lions Tour of South Africa in the same year and scored two tries before injury prevented him from claiming a Test place.
He won his last cap for Ireland, against England, in the Six Nations in March 2012 and was man-of-the match in the Heineken Cup quarter-final win over Munster a month later, as he helped Ulster to their first final since 1999.
His final appearance for the province was in the Heineken Cup quarter-final against Saracens at Ravenhill in April.
"It is every young rugby player's dream to represent their province and their country, and I have been enormously privileged to have done both," added Ferris.
"I have shared a pitch with so many talented players over the past nine years and I want to thank my team-mates at Ulster and Ireland for the support that they have given me.
"I also want to thank the IRFU, as well as the strength and conditioning coaches and medical team at Ulster, for all their hard work, patience and backing over the past year and a half."
David Humphreys, Ulster's Director of Rugby, is disappointed to be losing one of the game's top back-row players.
"I would like to thank Stephen for the outstanding contribution that he has made to Ulster," he said.
"We knew from the day and hour that he walked into the academy that he was an exceptional talent. Through dedication and hard work he developed into one of the best forwards in the world game.
"He has always played an important leadership role within the squad and he helped mentor and inspire others.
"While we are sorry to be losing Stephen, we recognise and celebrate the exceptional rugby career that he has had and wish him every success in the future."