The finishing touches have been put on his British record transfer from Liverpool, which could be worth up to £142 million, and the Spanish club are set to parade him at the Nou Camp.
The 25-year-old Brazil international, who watched his new side's 3-0 win over Levante on Sunday, will perform a ceremonial signing of his contract at 1130GMT on Monday before a photo shoot on the pitch and a press conference.
He told Barca TV: "I'm very happy, very happy. I have always said that it is a dream that I am living and I am very happy to be here.
"To be able to play, win titles, make the fans happy... always play with joy. It is incredible to know that I am going to live with idols, players with a lot of history.
"Footballers like Leo Messi, Luis Suarez, (Andres) Iniesta, (Gerard) Pique, (Sergio) Busquets. I am very happy to be able to live together, to be able to learn from them and be able to win together."
Liverpool have now turned their attentions to signing a replacement, while they are also trying to speed up Naby Keita's switch to the club.