London - Former Australia captain James Horwill extended his contract with English Premiership club Harlequins until 2020 on Tuesday.
The 31-year-old second-row forward - capped 62 times and captain of the Wallabies at the 2011 Rugby World Cup - has been with the club since joining from Super Rugby franchise, the Reds, in 2015.
"From the moment James joined 18 months ago, he has shown himself to be both a world-class player and an outstanding leader," director of rugby James Kingston told the club website.
"His infectious enthusiasm and drive illustrates exactly why he captained Australia on 16 occasions and he has proved a shining example to the rest of the squad.
"In extending his contract to the summer of 2020, he has crucially committed himself long term.
"This signing is a statement of our intent for the coming years."
Harlequins - who in 2012 won their only domestic league title - are presently sixth in the Premiership table after 10 games, 15 points adrift of leaders and defending champions Saracens.