“That dream is now a reality and an honour."
“There is so much more that I want to achieve here, and I know that is the same for the rest of the squad and staff. More than anything, we want to give the fans the success that they deserve.
“We have shared some great moments over the last years, but the best is yet to come from myself and this team.”
Manchester United's football director, John Murtough, said the club was happy to have finalised the deal.
“Everyone is well aware of Bruno’s importance to Manchester United. His goals and assists record is phenomenal and he has performed remarkably consistently since he joined the club.
“Bruno’s work-rate, dedication and fantastic attitude are exactly what we want from a Manchester United player. He is the ultimate professional with many fantastic attributes to drive the high standards required to play for this great club.
“Bruno, like everyone across the football club, remains hugely ambitious and determined to deliver sustained success on the pitch to get us back to challenging for titles.”