Sean O'Brien has agreed a new contract with the Irish Rugby Football Union that has tied him to Leinster until after the 2019 World Cup.
Having made his debut for the Dublin-based outfit in 2008, 28-year-old O'Brien has gone on to score 16 tries in 98 outings.
"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," he told the club's official website.
"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."
The flanker has been capped by Ireland on 41 occasions, from which he has contributed 35 points.
