Chelsea announced their eighth signing of the summer on Thursday when Aaron Anselmino joined a growing list.
Anselmino, 19, signed from Boca Juniors in Argentina for a transfer fee in the region of £15million before immediately returning to his former club on loan.
Chelsea tweeted via the club's official X account: 'Chelsea is pleased to announce the signing of defender Aaron Anselmino, who will spend the 2024/25 campaign on loan at Boca Juniors.'
Anselmino has signed a seven-year contract at Stamford Bridge.
He will become the latest player from Argentina to represent Chelsea - following in the footsteps of Hernan Crespo, Gonzalo Higuain, Juan Sebastian Veron, Willy Caballero, Franco Di Santo and current midfield star Enzo Fernandez.
Teenage defender Aaron Anselmino signed a seven-year contract with Chelsea on Thursday
Chelsea have spent more than £110m on new players since the end of last season, bringing in Omari Kellyman, Tosin Adarabioyo, Marc Guiu, Kiernan Dewsbury-Hall, Renato Veiga, Caleb Wiley, Filip Jorgensen and now Anselmino.
But more signings are still expected, with new manager Enzo Maresca keen to add another striker.
Chelsea have so far recouped nearly £90m through player sales this summer.
Ian Maatsen, Lewis Hall, Omari Hutchinson, Hakim Ziyech and Jamie Cumming have all been sold for seven-figure transfer fees, while Thiago Silva and Malang Sarr were released.
Conor Gallagher is also leaving Stamford Bridge this summer, with the midfielder set to move to Atletico Madrid.
Chelsea recently completed their tour of the USA, where they played five friendly matches.
They beat Club America and drew with Wrexham but lost to Celtic, Man City and Real Madrid.
Maresca's men will complete their pre-season schedule with a home game against Inter Milan on Sunday, before kicking off the new campaign by hosting Man City on August 18.