European champions Real Madrid on Friday beat Barcelona to the signature of 17-year-old Rodrygo from Santos in Brazil with the youngster expected to move to La Liga in 2019.
"Real Madrid and Santos have agreed that Rodrygo Goes will play his football at Real Madrid when he reaches the legal age requirement," said a Real statement.
"Although the player would be able to play for our club as of January 2019, the agreement in place sets out that he will join the squad in July of that year."
According to Marca newspaper, the deal is worth 45 million euros ($52m).
"It's a dream for me to be a player of Real Madrid, but my biggest dream has already been realised and that is to be a player for Santos," Rodrygo told a news conference in Sao Paulo.
"Everything has happened so quickly, I have spent half of my life here," added the teenager who has scored nine goals in 29 games for Santos, the iconic Brazilian club of Neymar and Pele.
He made his debut last November when he was just 16.
His agent Nick Aguri said that Rodrygo will pen a six-year deal with Real which will stretch to 2025.