The Irish Rugby Football Union (IRFU) and Leinster have announced that Sean O'Brien has signed a new three-year contract which will see him remain at Leinster until after the Rugby World Cup in 2019.
O'Brien made his senior debut for Leinster against Cardiff Blues in September 2008 and has since made 98 appearances for Leinster, scoring 16 tries.
He made his Ireland debut in the 41-6 win over Fiji at the RDS in November 2009 and the 28-year-old has won 41 caps for his country with his last appearance for Ireland a man of the match performance against France at RWC 2015.
O'Brien became the 104th player to captain Ireland when he led the team against Scotland in the build-up to the Rugby World Cup.
O'Brien toured with the Series-winning British and Irish Lions squad in 2013 and has won three European Cups, a Challenge Cup and two PRO12 league titles with Leinster.
IRFU Performance Director, David Nucifora said, "Sean is not only a proven world class player but he is a leader within the national set up and at Leinster. The IRFU are delighted that Sean has committed to playing in Ireland until after the next World Cup."
Leinster CEO Mick Dawson said "Sean is a very important figure within the Leinster set up and we are delighted to have secured his services for another three years.
"He is a great example to kids out there playing rugby that the 'Leinster Pathway' system that we have in place and the effectiveness of same in identifying and nurturing home grown talent from grass roots in Tullow up to the very top level of our sport, is working."
Commenting on the new contract O'Brien said "Growing up as a young lad in Tullow it was always my ambition to play for Leinster Rugby and Ireland so you never take moments like this for granted and I am very grateful for the opportunity to sign with a club that I feel is going in the right direction under Leo and the rest of the coaching team.
"I think we have a hugely talented group of players and coaches at provincial and national level and it is something that I want to be a part of."