Middlesex have confirmed that James Harris has agreed a new two-year contract with the club.
The 25-year-old, who has taken 36 wickets at an average of 21.55 this season, arrived at Lord's from Glamorgan in 2013.
"I am thrilled to have signed an extension to my current contract with Middlesex. I've been really pleased with my form in the early part of this season and am looking forward to this continuing for Middlesex for the remainder of this season and in years to come," he told the club's official website.
Meanwhile, director of cricket Angus Fraser added: "It has been great to watch James perform as well as he has this season. He has played a huge role in the club making a strong start to the season.
"The previous two summers have been tough for him but he continued to work exceptionally hard at his game and he is now getting the rewards his dedication deserves. James is the sort of character and cricketer that every team wants."
Harris's new deal will automatically be extended until 2018 if an agreed set of criteria are met.