LONDON (AFP) - Wayne Rooney pledged his long-term future to Manchester United on Friday after signing a blockbuster contract extension with the Premier League champions.

Mr Rooney had just 18 months left on his previous deal and was a transfer target for Chelsea last year, sparking speculation he could leave at the end of this season, but the England striker has agreed to extend his stay at Old Trafford until June 2019.

The new contract will reportedly pay the 28-year-old £300,000 (S$634,476) a week, with Rooney also set to stay at United as a club ambassador when he eventually retires.

"Wayne Rooney has committed his future to Manchester United by signing a four-year contract extension, keeping him at the club until June 2019. Wayne will also become a club ambassador when he retires from the game," a statement on United's website announced.