Wales wing George North has signed a new contract with Premiership club Northampton Saints.
The 23-year-old's previous deal was due to expire next summer.
North, capped 55 times by Wales and also a British and Irish Lions player, has appeared 42 times for Saints since joining from Scarlets in 2013.
"He is a proven world-class performer, something he has shown over and over again in his time here," said Saints director of rugby Jim Mallinder.
North had concussion problems last season, suffering four blows to the head in a five-month period, the final one of which came when he was knocked unconscious in the act of scoring his second try for Northampton against Wasps on 27 March.
Following that incident he was ordered to rest after being examined by a neurosurgeon, before returning to play for Wales in the World Cup.
He played in four of Wales' matches as Warren Gatland's side reached the quarter-finals before losing to South Africa at Twickenham.
North, who became the youngest-ever try scorer at a World Cup when he crossed against Namibia in 2011 aged 19 years and 166 days, added: "It has been a pleasure to play for this great club and for its fans, who are some of the best in rugby.
"It's been a fantastic couple of years where we have enjoyed much success and is a hugely competitive environment where I can continue to develop and improve as a player."
There had been speculation that North might return to a Welsh region, possibly on a dual contract with the Welsh Rugby Union, like the one which will bring centre Jonathan Davies back to the Scarlets from Clermont Auvergne next season.
But Mallinder had maintained he was "very, very confident" he would stay in England and he has now signed an undisclosed-length deal to keep him at Franklin's Gardens.