Midfielder Fred also got his black barnet newly coiffured and shaped, with a special gel added that made his spiky curls glitter.
Fred, who will become the fourth most expensive player in United history after Paul Pogba, Romelu Lukaku and Angel Di Maria, underwent a successful medical earlier this week.
The Daily Express says that the teenager has completed his medical and agreed personal terms, and an official announcement will be made in the next 48 hours with United "ready to pay nearly £20m" for his services.
Nigeria will face Czech Republic in their final 2018 pre-World Cup friendly on Wednesday afternoon at Rudolf-Tonn-Stadion Stadium in Austria.
"If I was a club manager, I would be looking to sign him".
The Shakhtar star will join the club after playing a vital part of the clubs successes across the last few seasons.
Fred was born in Belo Horizonte and moved to Europe in 2013 from Brazilian club Internacional.
He was at the centre of controversy in 2015 after testing positive for the the diuretic hydrochlorothiazide during the Copa America in Chile, and was banned for a year as a result.
Fred is renowned as a box-to-box all-action central midfielder.
With Michael Carrick retiring and Marouane Fellaini likely to leave, midfield was one area that needed his attention. He rates youngster Scott McTominay, but Fred is an experienced Champions League player and now a Brazilian global.
"It's very hard, I don't want to be emotional but I have to be", the Portuguese coach told RT.
Another cause for concern could also be the level of the Ukrainian league.
"You will have to see with him".
The Brazilian, who is now in England with the rest of his global teammates, was spotted at the training ground, with the fee rumoured to be around £52.5m agreed with Shakhtar Donetsk.
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