Romelu Lukaku officially completed his move from Everton to Manchester United on Monday for a reported fee of £75 million ($97m, 85.5m euros), a record deal between British clubs.
The 24-year-old Belgian international striker -- Everton's record Premier League goalscorer -- signed a five-year deal after passing his medical and agreeing personal terms which will see him earn over £200,000 a week.
"Romelu is a natural fit for Manchester United. He is a big personality and a big player. It is only natural that he wants to develop his career at the biggest club," said United manager Jose Mourinho on the club website.
Mourinho, who landed the League Cup and Europa League last term after spending big in 2016, including a world-record £89m on Lukaku's close friend Paul Pogba, added he was looking forward to collaborating with the Belgian again.
The Portuguese manager had sold him for £28m to Everton in 2014 during his second spell in charge of Chelsea.
"He will be a great addition to the group and I know they will make him very welcome," said Mourinho, who will take extra pleasure in having denied Chelsea their top transfer target of the close season. I am really looking forward to working with him again."
Lukaku, who turned down the most lucrative contract offer in Everton's history at the end of last term, said he was sorry to leave behind good friends at his former club but his head had been turned once United came calling.