England moved into the last 16 with a 3-0 win over Senegal to set up a mouth-watering clash with France after the reigning world champions brushed aside Poland, with Mbappe scoring twice to take his tally to five goals in Qatar.
The focus will be on whether Walker, who returned from groin surgery before the World Cup, can handle the blistering pace of Mbappe.
The defender, however, said they were not playing a "solo sport" like tennis but a team game where they would have to work collectively.
"I do understand what I need to do and that's obviously to stop him. It's probably easier said than done, but I don't underestimate myself. I've played him before," Walker said on Wednesday.
"I have to take extra care and give him the respect he deserves - but not too much respect because he's also playing England and we can cause them problems."
Walker described the game as "do or die", adding of Mbappe: "He's not going to stand in my way of hopefully winning a World Cup for my country."
FANTASTIC PLAYER
Walker played Mbappe when Manchester City knocked out Paris St Germain in the 2020/21 Champions League semi-finals, and they met again in the group stage the following season.
"Obviously the experience is always going to help," Walker added.
"He's a fantastic player in great form, so it's not going to be an easy task... I think he's one of the best, if not the best in the world at the minute."
England coach Gareth Southgate has been accused of playing with the handbrake on in the past, but Walker said confidence is high in the camp after they scored 12 goals in Qatar and conceded only two.
"It's a great opportunity to put a stamp down and say that we are a good team and we can achieve great things. I think that it will ultimately give us the belief that we can actually go on and win this," Walker said.
"To beat a big team like France in a quarter-final match, the reigning world champions, you've got to take some confidence from that - not arrogance, but confidence."
He also rejected the criticism of Southgate's handling of previous tournaments, saying the team and its tactics had evolved.
"We've moved forward in this tournament, playing really good attacking football and scoring goals."
Midfielder Declan Rice (23) did not train with the squad on Wednesday due to an illness, while striker Callum Wilson (30) was undergoing rehabilitation work in an indoor session.
