The Brazilian becomes the most expensive goalkeeper in history, costing an eye-watering £65 million ($85m) and taking Liverpool's spending well past the £150m mark.
A show of ambition, if ever there was one.
Alisson joins Naby Keita, Fabinho and Xherdan Shaqiri in moving to Anfield, as Jurgen Klopp seeks a Premier League title challenge this season, as well as another tilt at the Champions League.
But what do these arrivals mean for the Reds' current players? Who should be worried about their place?
Here's a look at how the new-look Liverpool could line up for the 2018/19 season...
The most likely move is for Klopp to stick with his tried and trusted 4-3-3 formation, the one which has served him pretty well throughout his managerial career.
The question then becomes 'which of his current crop finds themselves benched?'
At risk will be captain Jordan Henderson, whose role as the deepest-lying midfield player will be challenged by the excellent Fabinho. Keita, it is imagined, will slot in as a scuttling 'No.8' which will leave one or both of Gini Wijnaldum and James Milner on the sidelines. Emre Can has joined Juventus while Alex Oxlade-Chamberlain could miss the entire season with a knee injury. Adam Lallana, though, is back to compete for a place after a nightmare campaign last time out.
Another alternative is to switch towards a 4-2-3-1 system, which would enable Klopp to play ostensibly with four forwards. He did that to good effect on the final day of last season against Brighton.
Keita and Fabinho could form a formidable duo at the base of midfield, with Lallana (or Shaqiri, or even the resurgent Daniel Sturridge) slotting into the No.10 role behind Roberto Firmino. Firmino himself could also occupy that position, though Klopp prefers him as a No.9. Both Salah and Mane have played infield on occasion, too.
How about something a bit different? A return to the traditional old 4-4-2?
Liverpool have the players, with Shaqiri enabling them to move Salah (or Mane) to a more central position if they wished.
One for certain types of games, perhaps? Home games against lesser opponents, perhaps?