Liverpool have confirmed the signing of Philippe Coutinho for a fee believed to be in the region of £8.5m.
The Brazilian joins from Inter Milan and has signed a "long-term" contract with the Reds.
The 20-year-old told Liverpool's official website: "I'm feeling very happy, it's a very important step in my career and I'm expecting to come here and play good football to give my contribution on the pitch.
"Liverpool is a great club with great players. We've always heard about Liverpool's history in Brazil. They are the club that have been interested in me and that have showed this interest so I know they believe in me and my football."
The confirmation of Coutinho's switch to Liverpool appeared only a matter of time after pictures emerged of the Brazilian playmaker holding a Liverpool shirt.
The Reds agreed a fee with Inter Milan for the playmaker last week and the player had been on Merseyside to undertake a medical and discuss personal terms. The granting of a work permit had been a concern, however that has been taken care of.
Liverpool managing director Ian Ayre said: "We're always delighted when we get the players we go after.
"It has been a successful transfer window for us, coming off the back of acquiring Daniel Sturridge from Chelsea and now Philippe from Inter Milan.
"I think that bodes well for us for the rest of the season and the future."
Coutinho, who had also been linked with a switch to Southampton, will leave Italy with the blessing of Inter Milan president Massimo Moratti.
"There are opportunities there to be seized. Sometimes certain players need the chance to play more," Moratti told inter.it.
"And that's why I think this could be a great opportunity for a Coutinho, and a deal that could go very well for us too."
Inter paid £3.5m for Coutinho in 2008 when he was just 16. Big things were expected of him but last season he went on loan to Espanyol and his one Brazil cap came in 2010.
Coutinho becomes Liverpool's second arrival of the transfer window following the capture of Daniel Sturridge from Chelsea for £12m.