Rayan has leant on the advice of team-mate and former Liverpool star Philippe Coutinho, and has opted to join the Cherries for a club record deal of around for an initial £24.7m with a further £5.6m in potential add-ons.
The 19-year-old scored 14 goals in 34 games in the Brazilian Serie A last season for Vasco da Gama and arrives with the same reputation as Chelsea’s Estevao who is tearing up the Premier League.
Rayan commented on the move, stating how happy he is to land in Bournemouth ahead of the weekend clash against bottom of the league Wolves.
“I am very happy and very honoured to be here, especially with the sporting project they developed for me.
“I’m extremely happy. It’s a club that develops a lot of talents, so I’m very happy to be here and hope to give the fans a lot of joy.”
"Rayan is a player we have followed closely and who has already shown impressive consistency and maturity for his age," said Cherries president of football operations Tiago Pinto.
"We believe he has enormous potential, and Bournemouth is the right environment for him to continue his development and make an impact.
"I'm pleased that he chose our project as the one he committed to, and we're very excited to have him as part of our team, as we continue to reinvest in the squad."
The forward, who has drawn comparisons to the likes of Endrick and Vinicius has had his move funded by Antoine Semenyo, who joined Manchester City for £62.5m earlier this month as Bournemouth try to replace the Ghaha international.
talkSPORT journalist Alex Crook reports that his contract also includes a huge release clause which other clubs will already be eyeing:
"#AFCB new-boy Rayan understood to have a release clause as high as €100m in his contract. Shows how big of a coup the ???? think they have pulled off by landing the Brazilian teenage sensation. With @JacobsBen for @talkSPORT."