The Belgian striker is set to return to Stamford Bridge after his current club Inter agreed on a fee in the region of £97.5m with the Blues.
Lukaku spent three seasons at Chelsea between 2011 and 2014, but only made 15 appearances for them before signing for Everton.
The 28-year-old then moved to United for £75m in 2017 before being sold to Inter two years later for £73m. He is now expected to return to Chelsea after successfully helping the Italian giants win the Serie A title last season.
And while Chelsea will be re-signing one of the best strikers in Europe, the deal is also set to benefit United after they inserted a four percent sell-on clause into his contract when they sold him to Inter back in 2019.
The money will boost United who are looking to sell before making any more additions following the arrivals of Jadon Sancho and Raphael Varane already this summer.
The deal for Lukaku wasn’t straightforward- the Belgian was in no rush to leave Milan, while Inter were holding out for a fee in excess of £100m despite suffering from financial difficulties amid the Covid-19 pandemic.
Chelsea also offered a player-plus-cash deal which included left-back Marcos Alonso heading to the San Siro, but Inter firmly rebuffed the offer.
However, late last week the clubs finally agreed on a fee that would see Lukaku return to the Premier League, with the striker requesting to be allowed to leave.
The deal could also benefit United in their search for a new striker, too.
With Chelsea tying up a deal for Lukaku and Manchester City eyeing a move for Tottenham’s Harry Kane, it means United would have less competition should they attempt to sign Borussia Dortmund’s Erling Haaland next summer.