Teenager Reinier Jesus said he was fulfilling "a childhood dream" as he cried during his unveiling as a Real Madrid player.
The 18-year-old Brazilian attacking midfielder joined the La Liga club from Flamengo for £26m in January.
Reinier, who only made his senior debut on 31 July last year, was unveiled at the Bernabeu by Real Madrid president Florentino Perez on Tuesday.
"I want to be a part of the history of this great club," Reinier said.
"Today is a very happy day for me as I get to fulfil a childhood dream."
Reinier was part of the side that won the Brazilian league and the Copa Libertadores last season and was an unused substitute in December's Club World Cup final against Liverpool.
He is the third Brazilian teenager to join Real in the past two years after Vinicius Junior and Rodrygo.
"It is our obsession to look for players who could be the big stars of tomorrow," said Perez.
"Today we welcome a player who has just turned 18 but has already won the Copa Libertadores with Flamengo, one of the biggest clubs in the world."
Real are also in the process of renovating their Bernabeu stadium.
"As we aim to build the best stadium of the 21st Century, we are obliged to develop the talent of the future," added Perez.
"It's not easy to find unquestionable talent that can make you form part of Real Madrid's legend."