England and Harlequins forward Nick Easter has announced his retirement from rugby.
The 37-year-old will now take on a full-time coaching position with Harlequins, the Aviva Premiership club have announced.
Easter accepted a role as coach-player of Quins in April, taking charge of defence.
Easter said: "After accepting the opportunity of being a coach-player by (Quins director of rugby) John Kingston, I took some time to think about my career. I realised that whether I'm playing or coaching, there was no possible way that I would be able to give 100 per cent to both of my roles at the same time."
He added: "I thought, why not grab the opportunity of becoming a coach with both hands, give it my best shot and feel privileged to be in a position to go out on my own terms after 12 great years as a player for Harlequins.
"I'm a few weeks into my role now and I'm thoroughly enjoying it. Having had five weeks in the off-season to finalise it and four weeks now as a coach, I don't regret my decision and I can't wait for the new season to begin."
Easter has called time on his playing career after making 281 appearances for Harlequins since joining the club from Orrell in 2004 - making him Quins' most capped professional player.
During his time at the Stoop, Easter has helped Quins win the Amlin Challenge Cup in 2011, their maiden Premiership title the following year and the LV Cup in 2013.
Kingston said: "Nick has a fantastic rugby brain and it is for this reason I offered him the opportunity to join the new-look coaching team at the club."
Easter also won 54 caps for England, making his debut against Italy in the 2007 RBS 6 Nations. In the same year he played in the World Cup final defeat to South Africa and became the first Red Rose number eight to score four tries in one match, a feat he achieved in the 62-5 win over Wales.
After a lengthy international absence, Easter was recalled by England for last year's Six Nations and was then summoned into Stuart Lancaster's World Cup squad as an injury replacement for Billy Vunipola.
In England's final pool game at the World Cup, Easter became the oldest hat-trick scorer in Test history after crossing three times in victory over Uruguay, earning him the man of the match in his final appearance for country.