River Plate forward Franco Mastantuono has officially signed his contract with Real Madrid and will join the club on August 15, right after turning 18, sources from the Argentine club confirmed to EFE on Wednesday. The move was sealed through the activation of his €45 million release clause.

The most expensive transfer in Argentine football history

On top of the €45 million fee, another €15 million will be paid in taxes, making this the most expensive transfer in Argentine football history. Although Mastantuono is set to arrive in Madrid by mid-August, he will stay with River Plate to compete in the Club World Cup, which kicks off this weekend.

The contract was signed after the youngster passed his medical in Buenos Aires, following his call-up with the Argentine national team. At just 17 years and 295 days old, Mastantuono recently made his senior debut for La Albiceleste in a 1–0 win over Chile during the 2026 World Cup qualifiers.

A rising star in Argentine football

Born in Azul, Buenos Aires Province, the young talent has had an impressive first half of the year with River Plate, scoring seven goals and providing four assists in 19 appearances. His standout moment came with a stunning free-kick goal against Boca Juniors in the latest Superclásico. Typically used as a right winger, Mastantuono loves to cut inside on his favored left foot.

On Tuesday, he didn’t feature in Argentina’s 1–1 draw against Colombia at the Monumental Stadium. Now, he’s headed to Seattle with the River Plate squad to play in the Club World Cup under Marcelo Gallardo’s leadership. River Plate is in Group E alongside Inter Milan, Monterrey from Mexico, and Urawa Red Diamonds of Japan, whom they’ll face in their tournament opener next Tuesday.