But Heskey thinks Borussia Dortmund winger Sancho would be a wiser signing over Mbappe and Erling Braud Haaland.
"I'd choose Sancho for Liverpool, out of the three," he told Genting Bet.
"Mbappe is a phenomenal player who is another player who keeps on rising and is only going to get better and better. He's focused more to keep the consistency going at that age is just phenomenal.
"It's difficult, because for Liverpool you'd choose a player who was more on the wing than central. But again, [Erling] Haaland's goals are a key factor.
"I'm going to be patriotic and say that Sancho would be great, being an England player and an entertaining player as well. I would say someone like that would be great to get on the wing and terrorise defences."