Simon Mignolet has completed a move to Liverpool on a long-term contract.
The 25-year-old made 101 appearances for Sunderland after joining the Wearside club from Sint Truiden in 2010, but will now look to compete with Pepe Reina for the number one jersey at Anfield.
Liverpool have been busy in the market already in the off-season, signing Spanish duo Luis Alberto and Iago Aspas, as well as Kolo Toure, with manager Brendan Rodgers enthused by the shape his squad is taking.
"I am delighted that we have been able to sign one of the top goalkeepers in the Premier League," said Rodgers.
"Simon will join a club that will give him an opportunity to demonstrate and improve his huge talent."
Sunderland boss Paolo Di Canio lamented the departure of his first-choice goalkeeper, but insists he is immediately on the hunt for a replacement.
He said: "Simon is a fantastic footballer, a fantastic professional and a fantastic lad and I would like to personally thank him for his contribution to the team last season.
"He was crucial to what we achieved and he goes with the very best wishes of everyone at the club. I would like to assure our fans that there is a huge amount of work going on behind the scenes.
"Our aim is to build a competitive squad for the new season and this deal will give us further ability to strengthen the side."