The Guinea international finalised the formalties of a transfer for next summer on Monday after the Reds agreed to pay a premium over his release clause to tie up a deal in advance.
As revealed by Goal in March, he was identified as Jurgen Klopp’s priority target to dynamise the midfield.
The Bundesliga outfit refused to sanction a sale in this window, however, rejecting two bids - the second of which equalled the record for a transfer in Germany’s top flight - as they were intent on fielding the 22-year-old during their debut season in the Champions League.
The clubs have reached a conclusion that suits all parties though, with the Merseysiders activating the £48 million escape stipulation in Keita’s contract that comes into effect at the end of this season as well as offering an extra sum to wrap up matters now.
The player, capable of operating as an offensive and defensive weapon with equal adeptness, will be Liverpool’s record signing, eclipsing the initial £36.9m spent on Mohamed Salah.
However, if the Reds succeed in prising Thomas Lemar from Monaco ahead of Thursday's deadline, that business will shatter both figures with the current proposal worth over £70m inclusive of add-ons.
The Ligue 1 champions have resisted approaches for the 21-year-old all summer following an already extensive talent drain, but the multi-faceted playmaker is keen on a switch to Anfield.