He's had a brilliant season with the club, and Klopp is eager to heap praise on the feisty, clever attacker whom he's trusted to lead the line.
"I didn't know about the special story [of several players moving from Southampton to Liverpool], but now I do".
An agreement was finally reached for long-standing target Van Dijk, with a club-record deal pushed through on January 1. But we are all human beings, we are influenced by circumstances. It won't be a normal game.
"How football fans are, they want to disturb everything we try to do because they want to help their team, and probably they will whistle". Will it have influence?
'I sleep twice before we play Southampton so maybe I'll change my mind so we will see'.
"It's obviously quite special, but it was not in objective", said Klopp of his five former Southampton players, and joked that his side would not be able to field a team if they left their former-Saints contingent out of the side.
In a recent interview, for as much as these things really matter, Firmino has come out saying that he's very happy with his situation in Liverpool and hopes to remain with the club for the foreseeable future.
"Obviously it will be nice to see the players I have played with and the friends I have there but, for me, it is going to be about one thing only and that is to win the game".
Klopp, meanwhile, has spoken with Adam Lallana in recent days about his conduct and reminded the midfielder that he can not act in the way he did during an Under-23 game at Tottenham when he was sent off for violent conduct. He was already a few times back this season, so will not rush him back.
'He had 60 minutes roundabout.
On the affection he has from the fans, Firmino said: "I feel very good here in Liverpool".
Lallana is back in the squad despite his sending-off in the under-23s' defeat at Tottenham on Monday, when he reacted to a bad challenge, as the suspension does not apply to first-team fixtures.
"I'm not surprised that he is really, really fantastic and exactly like what we would have expected", Klopp said.
'Adam didn't play football and he was fine with it, it had nothing to do with the fact he was angry he had to play under-23s.
On speculation linking him with a move away from Anfield, Firmino was keen to add: "In every transfer window we hear a lot of speculation, but nothing concrete has come to me until now".