The France striker did not start in PSG's 1-0 first-leg loss to the Germans in Paris last month, coming on as a second-half substitute following a minor injury.
He will play on Wednesday, however, as they look to turn around the tie, having netted 30 times in all club competitions this season.
"The most spectacular is Kylian," Bayern attacking midfielder Thomas Muller (33) told a news conference on Tuesday when asked about PSG's best player in a team who also have world champion Lionel Messi (35) and Brazil international Neymar (31).
"I think it is a relatively easy decision. It is his explosiveness in combination with the right decisions in the box and he also goes where a striker needs to go," Muller said.
"He is effective and not just beautiful to watch. The whole world likes to watch him play but we will not be watching him tomorrow. We will be causing him trouble. If our plan goes well he won't have fun tomorrow."
Mbappe became Paris St Germain's all-time top scorer on Saturday with his 201st goal in all competitions, netting in a win over Nantes that extended their lead at the top of the Ligue 1 standings.
"Mbappe is a player who with his profile poses a danger for us. He represents most goals for Paris and we have to plan how to stop him but it is a team sport," Muller said. "It also about stopping him getting the passes, getting the spaces."
PSG will be without Neymar, who has been ruled out for the rest of the season with an ankle injury.
"The absence of Neymar does not change things too much. The fact that Mbappe plays from the start does change things," Bayern coach Julian Nagelsmann (35) said.
"He has unique qualities but it is about solving the problem collectively and I think we are well prepared."
