The Brazil number one became the world's most expensive keeper earlier this week when swapping the Stadio Olimpico for Anfield for a fee in the region of £67m.
Alisson has previously spent a season with Salah at Roma and, a year after the Egyptian left for Merseyside, Liverpool's latest addition has revealed that he received a text from his friend when discussions between the clubs were ongoing.
"We didn't have that much contact after he left Roma. We met again in the game when we were up against each other [in the Champions League in April]," he told his new side's official website.
"[Then] he sent me a message saying: 'Hey, what are you waiting for?' As the negotiations were at an advanced stage, I replied to him straight away saying: 'Calm down, I'm on my way!'
"I'm really happy to have the opportunity to play alongside him again. As well as being a great player, he is a huge character and a great person - which is the most important thing. To be with these great people and players day to day is fantastic for me."