The Premier League champions have long been negotiating for Lukaku, with Everton demanding £100m, but United have brokered a deal £25m under that price tag according to the BBC.
Wayne Rooney is expected to move the opposite direction in a deal that is not linked to Lukaku’s move, though talks for the veteran striker helped to smooth negotiations.
Jose Mourinho has always seen the Belgian as his first-choice target to succeed Zlatan Ibrahimovic at Old Trafford, who left the club when his one-year contract expired at the end of the season.
However, United had feared that Lukaku’s preference to return to Chelsea and prove himself in west London would hamper their chances of securing a deal.
Romelu Lukaku's Premier League season Games played37Goals scored25Assists6
But as talks with Real Madrid for Alvaro Morata stalled, United pressed ahead to wrap up a deal for Lukaku, having been working quietly behind the scenes to hijack Chelsea’s move.
The transfer will be a major coup for United, and another major source of frustration for Antonio Conte who has become increasingly irritated by Chelsea’s inability to tie up deals quickly.
With a fee agreed and terms with Lukaku unlikely to be a sticking point, the Belgian could even be on the plane when the squad fly out for the beginning of their pre-season tour on Sunday afternoon.
Lukaku just missed out on the golden boot last season, scoring 25 Premier League goals and registering a further six assists in a superb campaign.
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Although Mourinho sold the Belgian while at Chelsea, he has been massively impressed by his development at Everton.
A deal for Lukaku appears to end United’s interest in Morata, with the club unlikely to spend in excess of £150m on the two strikers despite Mourinho’s desire to significantly bolster his strikeforce this summer.