Xabi Alonso in the dugout during Chelsea's pre-season game against Tottenham in Sydney
Valentin Barco has signed a seven-year contract at Chelsea to join from sister club Strasbourg.
The 22-year-old, who used to ply his trade at Brighton, completes his move to the Blues with the deal being agreed ahead of the summer.
Valentin Barco for Strasbourg.2
Barco brings some Premier League experience on his return to England
He initially signed for Strasbourg on loan from Brighton in February 2025, before completing a switch worth £8million in July of that year.
Barco made seven appearances for the Seagulls ahead of his transfer to France, where he worked under former Chelsea boss Liam Rosenior.
Chelsea have opted to press ahead with the deal despite Rosenior being sacked from his post.
Barco was part of Argentina's World Cup squad this summer, playing in their group stage victory over Jordan.
But as a midfielder, he could face plenty of competition at Stamford Bridge when he arrives later this year.
Moises Caicedo, Enzo Fernandez, Romeo Lavia and Dario Essugo are midfield options at the disposal of new manager Xabi Alonso.
However, Barco could have one less competitor amid the uncertainty over Fernandez and his future in west London.
Barco in, Fernandez out?
After Chelsea were thrashed 8-2 on aggregate by Paris Saint-Germain in the Champions League in March, Fernandez criticised the club's board.
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He said he didn't understand their decision to allow head coach Enzo Maresca to leave the club at the beginning of the year.
Fernandez then generated speculation over a move to Real Madrid as he admitted he would like to live in the Spanish capital.
Enzo Fernandez in Champions League action for Chelsea in their round-of-16 second-leg defeat to PSG2
Barco could end up replacing Fernandez should he leave the club
talkSPORT understands he is open to a move to Madrid this summer, although the Spanish giants publicly denied their interest in Fernandez in July.
Fernandez was subsequently sanctioned for the comments having been prevented from playing Chelsea's FA Cup win over Port Vale in April, which finished 7-0 to Chelsea.
He was also not involved in their Premier League fixture away at Manchester City on April 12 as well.
Busy summer
Barco is the latest addition for Chelsea, which has seen them splash out on numerous summer signings.
They broke the transfer record for a British player with the £117million acquisition of England star Morgan Rogers from Aston Villa.
Meanwhile, France centre-back Maxence Lacroix has joined in a £52m deal from Crystal Palace.
The Blues announced the signing of former Arsenal and Manchester United striker Danny Welbeck on a two-year deal.
And former Liverpool captain Jordan Henderson is set to complete his move to the west London club imminently.