Real Madrid have agreed a €30m deal with Flamengo for Reinier, with the move now set to be officially completed when the player turns 18 later this month.
The 17-year-old has really caught the eye this season, registering six goals and two assists since breaking into the first team in August.
His performances have attracted the attention of a wealth of European clubs, including PSG, Barcelona and Manchester City, but Real Madrid have now won the race for his signature.
Globoesporte and Marca have each reported in the last few hours that Los Blancos have now agreed to pay out the player's release clause, which stands at €30m, but will complete the deal on January 19 (his 18th birthday) in order to comply with FIFA transfer laws regarding youth players.
Real Madrid's new signing, often compared to Kaka, will initially join Real Madrid's Castilla side - coached by Los Blancos' legendary former striker Raul, but is set to participate with Brazil's Under-23 squad in a pre-Olympic tournament first. The campaign starts later this month and could see Reinier stay with the squad until February 9, should Brazil reach the late stages.
He will join up with Castilla upon completion of the tournament.
Rivals Atletico Madrid had reportedly held talks with the skilful midfielder, and at one point were the favourites to land the young prodigy.
However they were not prepared to pay Reinier's release clause, which at the time of negotiations was still €70m.
The contract the midfielder signed in November extended Reiner's Flamengo deal until 2024, though did see his release clause more than halved. The youngster would have been able to sign for any club in July 2020 had he not penned the new deal.
Flamengo need to raise funds in order to keep to their budget for this year, and are therefore willing to part ways with one of their prized assets.
Reinier will join up with four fellow Brazilians at the Bernabeu; Marcelo, Rodrygo, Vinicius Jr, and Casemiro.