Mbappe, who scored 21 times in all competitions for Paris Saint-Germain last term, has netted three times in five appearances for France at this year's World Cup.
The teenager netted a brace against Argentina in the round of 16, and was also in impressive form against Uruguay on Friday, with Les Bleus winning 2-0 to book their spot in the semi-finals.
Hazard's Belgium team will take on France in the last-four stage of the World Cup on Tuesday night, and the Chelsea attacker has revealed his admiration for Mbappe.
"Mbappe? I have spoken to him on the phone quite a few times," Hazard told beIN Sport. "He watched footage of me when he was a kid. Now I watch footage of him! I have mad respect for what he does at his age. In modern football, it's unheard of."
The winner of France and Belgium will take on the victor of the second semi-final between England and Croatia in next weekend's final.