Ashley Young is the second confirmed new arrival at United this summer, after Phil Jones agreed a move from Blackburn Rovers earlier this month.
A club statement on Thursday afternoon read: “Manchester United is delighted to announce it has reached agreement with Aston Villa for the transfer of Ashley Young. The player passed a medical in Manchester and has agreed a five-year contract.”
Young made 193 appearances and scored 39 times for Aston Villa after joining them from Watford in January 2007. The 25 year-old winger or second striker is renowned as a chief creator of goals - in the last five Premier League seasons, only Arsenal midfielder Cesc Fabregas provided more assists for his team-mates.
In an exclusive interview with MUTV, Young admitted he will miss the "fantastic" fans and staff at Villa Park but explained "the opportunity to come and play for one of the biggest clubs in the world is one I couldn't turn down.
"It's a chance to... hopefully become part of the history by helping to win the 20th title."
Reds defender Rio Ferdinand welcomed the deal on Twitter, hailing his England team-mate as "another top, hungry and young player".