FC Barcelona and Ansu Fati have reached an agreement over a new contract which still runs until 2022 -- with the option for two more -- with his release clause rising to 170 million euros.
In addition, that clause will rise to 400 million euros once he's officially promoted to the first team.
The terms were signed on Wednesday at the club's offices. President Josep Maria Bartomeu, director Silvio Elías and CEO Òscar Grau were all present.
Also in attendance were sporting director Éric Abidal, his assistant Ramón Planes Barça B director José Mari Bakero and director of youth football Patrick Kluivert.
Barça said: "Anssumane Fati (31/10/2002) has made a meteoric rise to fame since arriving at the club in 2012 when he was just ten years of age.
"He has gone on to become the youngest Barça player to ever score a Liga goal when he was just 16 years and 304 days old, and he is also the youngest Barça player to start a game at Camp Nou or appear in the Champions League."
Ansu added: "For me, La Masia is the best school in the world. They helped me from the first day I arrived and I am extremely grateful to everyone who works there. They are all spectacular. From the first day I have learned things from everyone. And they have also been there to support me through difficult times.
“Working every day with the best is a dream, and also a reward. From now onwards, what I have to do is keep working, even harder than ever, to keep getting chances and carryon on enjoying myself. The rest will come after.”