Liverpool secured a deal for Keita in August 2017 after triggering his £48m release clause. The transfer will go through on 1st July 2018 - RB Leipzig chief Oliver Mintzlaff has denied it will happen any sooner despite ongoing claims it could - and excitement is already growing.
Keita and Mane were formerly team-mates at Red Bull Salzburg in Austria prior to the latter's move to Southampton at the end of summer 2014.
Given that Keita, who moved to Leipzig in 2016, had joined from French club FC Istres earlier that summer, their time together was only brief. But it was still long enough to create a strong bond between the two that promises to help Keita settle when he makes the Merseyside switch.
"I think it just came normally because we speak the same language and we were close neighbours (in West Africa) - Guinea and Senegal," Mane explained to Liverpool's official YouTube channel when speaking about his friendship with the soon-to-be new arrival.
"When he came, we lived in the same area of Salzburg. We were always together, sometimes he came to my house, sometimes I went to his house," the winger added.
"We didn't even speak German, but we had someone to look after us. We're so close. Not even a friend, like a brother. We keep in touch all the time, talking."
Mane doesn't believe he is the reason Keita chose Liverpool, but did admit his friend asked him about life as a Reds player.
"He asked me how is the club, so I said 'unbelievable'. I don't think it was me who convinced him [to sign], but the team, the club, he knows," Mane commented. "I'm excited, but I'll have to wait until next season. We're lucky to have him because he's an unbelievable player, you will see."