Liverpool have agreed a deal to sign Monaco midfielder Fabinho from July 1 for a fee of up to 50million euros (£43.7million).
The Brazilian has been identified as a replacement for Emre Can, who is out of contract at Anfield this summer and has been heavily linked with a move to Juventus on a free transfer.
Press Association Sport understands Liverpool will pay Monaco 45million euros, plus a potential further 5million euros in add-ons, for a player who is expected to occupy a holding role in the middle of the park.
Fabinho, capped four times by his country but omitted from their World Cup squad, had no hesitation in signing a "long-term contract" with the Champions League finalists.
He told the club's official website: "I am really excited about this move.
"This is something that I always wanted - this is a giant of a team. The infrastructures of the club look exceptional.
"A football club of this size coming after my services, I didn't have to think that much about coming over.
"I will try to create my own history at this football club. Hopefully, on a personal level, I'm able to win titles with this club.
"I will try to grow and learn and improve myself, and to be part of the club's history."
Reds boss Jurgen Klopp was equally thrilled at the deal.
"We have signed a fantastic player, but someone who is an equally fantastic person I think," the German said.
"His reputation as a character in the dressing room and his attitude in training has come through from everyone we speak to.
"He has a lovely family also - adding a person like this to our dressing room only makes us even stronger. What we have - in terms of our environment at Melwood and in the team - means anyone coming in must be of that build. They must be the highest quality person and player."
Fabinho spent two seasons on loan at Monaco from Portuguese club Rio Ave before making a permanent move to the principality in May 2015.
The 24-year-old made more than 200 appearances for the club in all competitions and played a key role in their triumphant 2016/17 Ligue 1 campaign.
He will link up with his new club on the same day as fellow midfielder Naby Keita, who agreed to join Liverpool from RB Leipzig last August.