Fabinho will officially become a Liverpool player on July 1 after agreeing a "long-term contract" at Anfield in a deal which could rise to almost £44m.
The 24-year-old, who has four caps for Brazil, made his name during a five-year stint at Monaco, and Klopp believes that he will be an important addition to the team both on and off the field.
"We have signed a fantastic player, but someone who is an equally fantastic person I think. His reputation as a character in the dressing room and his attitude in training has come through from everyone we speak to," Klopp told Liverpool's official website.
"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.
"He has ability and mentality to play at the highest level in a number of positions. He can play '6', '8' and '2'. This is cool. He is tactically very strong and football smart. I think he improves our squad and there aren't that many players you can say that about in this moment, because the quality we have already is so high.
"I like that he is young yet experienced also, with a high number of games at a club that compete to win. Also, international caps for Brazil tells you something about him. This signing gives us new opportunities and for that I am excited. I'm sure our supporters will make him very welcome and at home at our wonderful club and in our amazing city."
Fabinho's arrival is expected to pave the way for Emre Can to leave the club when his contract expires this summer.