Lionel Messi has agreed upon a three-year extension with Barcelona through 2021.

Messi's current deal was set to expire in 12 months and his release clause has been elevated to €300 million.

"The club is very happy with both the renewal and the commitment of Messi, the best player in history," Barca said in a statement.

"He has played his full professional career at Barca and has led the team to an era of extraordinary success, the likes of which has never been seen in world football."