Philippe Coutinho has completed his move from Liverpool to Barcelona for a fee understood to be £146m.
The Brazil international underwent a two-part medical early on Monday, which revealed he had a thigh injury which will delay his debut by three weeks.
Coutinho then headed to the Nou Camp where he joined Barcelona president Josep Maria Bartomeu to sign a contract until summer 2023.
The 25-year-old's Barcelona contract includes a 400m Euros (£354.6m) buyout clause.
Sky Sports News understands Inter Milan did not have a significant sell-on clause in the deal that saw Coutinho move to Liverpool for £8.5m in 2013.
Coutinho said: "I want to thank the president and all those who have made possible the signing.
"I am very happy, it is a dream come true and I hope to meet all expectations in the field."
Coutinho was the subject of three failed bids from Barcelona in the summer, the largest of which was worth £113m, and he handed in a transfer request in an attempt to force a move but was unsuccessful.
Bartomeu said: "We've been working for months on this. But one of the important aspects was that he [Coutinho] wanted to come here. He made an effort, he was patient and that was a determining factor in bringing him here.
"Everybody knows him as a player, we know about his professional career, but what I can say is that it wasn't easy to bring him here. He wanted to be here and he's part of this new project with [Ernesto] Valverde.
"I want to thank Liverpool, one of Europe's biggest clubs, for allowing him to leave."
Coutinho has already played for Liverpool in this season's Champions League, and will therefore be ineligible to play for Barcelona in the competition during the current campaign.
Liverpool, meanwhile, will not be able to move Naby Keita's transfer from RB Leipzig forward, according to Sky in Germany.
The transfer has already been agreed for the summer at 75m euros (£66.4m) but the club are not willing to let him go in January, even for an improved fee.