Manchester United have completed the signing of Netherlands international Alexander Buttner from Vitesse Arnhem, the club have announced.
The 23-year-old left-back, who completed a medical and agreed personal terms on a five-year contract, is understood to have cost in the region of £3.9m.
United manager Sir Alex Ferguson told the club's official website: "Alexander is one of the best young left backs in Europe and we're delighted to sign him.
"He's someone we've been watching for a while now. He gives us some really exciting options in that position."
Buttner, who was a part of the Netherlands preliminary squad for Euro 2012 before being axed from the final 23 players who travelled to Poland and Ukraine for this summer's tournament, said: "Joining Manchester United is one of the best days of my life. It's a team I have admired for many years now and I can't wait to join my teammates and play my part in helping the club be successful."
Buttner, who becomes the second Dutchman to move to Old Trafford in the past few days with Robin van Persie joining from Arsenal last week, is excited about joining up with his countryman.
"If a week ago, you told me that together with Robin van Persie I would be playing at Manchester United, I would have driven you straight to the madhouse," he said before leaving Schipol Airport in Amsterdam bound for Manchester.
The arrival of Buttner, who scored 10 times in 107 appearances for Arnhem, will provide competition for Patrice Evra. The long-standing United left-back suffered a dip in form last season and there have been questions about the Frenchman's defensive abilities.
With Fabio da Silva joining QPR on a season's long loan, Buttner will at the very least provide back-up in the left-back position.