Chelsea have completed the signing of midfielder Romeo Lavia from Southampton for a reported £53 million ($67.3 million), possibly rising to £58 million, taking their total number of first-team acquisitions this summer to eight.
The 19-year-old, who has played just 29 times in the Premier League, has signed a seven-year deal having made clear earlier this week his desire to move to Stamford Bridge over Liverpool, who also had a bid accepted.
Chelsea have now spent more than £350 million during this transfer window once performance-related add-ons are taken into account, though that has been significantly offset by fees received for player sales.
Lavia told the club's website: "I can't wait to meet all my new team-mates and build a chemistry together to achieve great things together."
Lavia, who made his Belgium debut in a friendly win against Germany in March, will likely compete with Enzo Fernandez and fellow new-signing Moises Caicedo – the two most expensive players in English transfer history – for a starting place in Mauricio Pochettino's midfield.
Chelsea broke that record for the second time in eight months on Monday with the capture of Caicedo from Brighton for an initial £100 million, possibly rising to £115 million, eclipsing the £106 million they paid Benfica for Fernandez in January.
Co-sporting directors Laurence Stewart and Paul Winstanley said: "We are very pleased to welcome Romeo to Chelsea.
"He demonstrated his quality in the Premier League last season at Southampton, showing maturity despite his young age, and is a player we have monitored for some time."
The PA news agency understands that a deal is yet to be agreed with Newcastle for defender Lewis Hall, though a move for the 18-year-old is close.
Hall signed a new six-year contract with the club just days ago and was set to spent the season on loan at Crystal Palace but Newcastle's offer, believed to be £28 million, has persuaded the club to reconsider.
As an academy product, any sale would be recorded as pure profit in Chelsea's books as they look to remain within Financial Fair Play rules following a total transfer outlay over the last year in excess of £900 million.
A deal had also been agreed with Palace for the transfer of winger Michael Olise after the club met his £35 million release clause, but the France Under-21 international has opted to remain at Selhurst Park and signed a new four-year contact on Thursday.
