The Atletico Madrid striker will be "pivotal" to Les Bleus chances in Russia, according to his teammate Mbappe.
"I think that he is the boss since the Euro already," he said Wednesday.
"When you end the European Championship the best goal-scorer in your own country, you show the world that you have the shoulders to handle the pressure.
"It's true that he went through a bad patch following the competition but he showed how [much of] an amazing player he was and he is by scoring goal after goal.
"He will be pivotal for us if we want to get results."