Britain's most expensive-ever signing will be officially presented to the media at 3pm - and you can watch his news conference live on Sky Sports News HQ.
The number seven shirt is among the most prestigious at Old Trafford, and has been worn by some of their most famous players including David Beckham, George Best, Eric Cantona, Bryan Robson and Cristiano Ronaldo.
Di Maria completed his move - for a British record fee of £59.7million - on Tuesday, signing a five-year deal.
The midfielder revealed United were the only club he was willing to leave Madrid for, and said he cannot wait to work with Louis van Gaal.
"I am absolutely delighted to be joining Manchester United," Di Maria told the club's official website.
"I have thoroughly enjoyed my time in Spain and there were a lot of clubs interested in me, but United is the only club that I would have left Real Madrid for.
"Louis van Gaal is a fantastic coach with a proven track record of success and I am impressed by the vision and determination everyone has to get this club back to the top - where it belongs.
“I now just cannot wait to get started."