Mbappe, 23, has been a shining light at the Qatar showcase with five goals from three starts to propel the holders into another last-8 showdown. England, meanwhile, have clocked up three wins and coasted past Senegal to book their place in the quarters.
Manchester City defender Walker suffered an injury before the tournament, but recovered in time to start against Wales and then last-16 opponents Senegal on Sunday night. He is now ready for his biggest fitness test yet against jet-heeled and free-scoring Mbappe.
That individual battle has created an intriguing subplot before the teams collide the Al-Bayt Stadium on Saturday night. Of course, the two have met before in the Champions League and Walker is generally regarded as one player who could potentially stop the Paris Saint-Germain attacker.
For once, at least, Mbappe knows he will not have it all his own way. Indeed, he even namedropped Walker when asked to select his fastest opponents – shortly after their most-recent European meeting.
Mbappe was pressed on that hot topic during an interview with France Football at Euro 2020 last summer. So why does “tank” Walker present such a challenge to him?
Mbappe said: “I was speaking with my father about a player who impressed me from the stands, because I was not playing. Because of his speed qualities, that was [Jeremy] Doku at Rennes. In five years as a professional I have never seen someone from a standing start demonstrate so much power.