The Dutch midfielder joins from Bayern Munich for a reported fee of £34.2million, a year after joining the German giants for £15m from Ajax.
There had been late fears that Bayern would pull the plug on the deal after their bid for Fulham’s Joao Palhinha collapsed, with the Portuguese star eyed as Gravenberch’s replacement.
Alas, Liverpool were still able to complete the deal after the 21-year-old completed a medical on Friday afternoon.
“I’m very happy,” he told the club website. “Very happy that the deal is done and I’m finally here.
“If you see it from the outside, it’s one of the biggest clubs in the world. Also the fans, the stadium, I think everything from the outside is top. So that’s why [it was the right club].”
Gravenberch has signed a long-term contract at Anfield, subject to a work permit, and will take the No38 jersey.
However, he will not be available to make his debut on Sunday against Aston Villa due to the deal not going through in time.