Zinedine Zidane's charges are aiming to claim a record third tournament crown on the bounce after staving off a memorable fightback from Juventus during the quarter-finals.
Bayern welcome the visit of Real under the stewardship of a coach who has enjoyed remarkable success in the Champions League.
Heynckes is featuring in his fourth campaign in Europe's elite competition and the coach has somehow managed to lead his sides to the final on the three previous occasions - twice with Bayern and once with Wednesday's guests.
The Monchengladbach-born boss had also won 12 straight Champions League fixtures before the club's recent 0-0 draw at home to quarter-final opponents Sevilla. The 72-year-old is a veteran in getting things done. Heynckes has a Champions League title with both Real and Bayern, alongside four Bundesliga crowns with the Bavarian club.
After being installed as a caretaker following the departure of Carlo Ancelotti, the German's minor tweaks and motivational talents contributed to a swift turnaround in fortunes for Bayern, who have now claimed another league title at a canter having once been in a rather sticky position earlier on in the campaign.
With the title in the bag, Bayern recently pushed on towards securing the DFB Cup having thumped Bayer Leverkusen 6-2 to establish a final meeting with Eintracht Frankfurt. Frankfurt coach Niko Kovac will be taking the Bayern reins off Heynckes when he departs the Allianz Arena in the summer. The coach will be hoping to do so with a treble in the bag, and only a handful of games now stand in the manager's way.
Wednesday's fixture will be the 25th European meeting between the sides, making it the most played out contest in any UEFA club competition. As things stand, Bayern and Real have both won 11 of those matches, drawing the other two.
Bayern frontman Robert Lewandowski, who has been constantly linked with a move to the Spanish capital, comes into the game having broken records this season in the Bundesliga. Over the weekend, the 29-year-old Polish forward became the most prolific non-German for a single club in the history of the league having notched his 105th top-flight goal for Die Roten.
Having been beaten by RB Leipzig in March, Bayern welcome Madrid having won four Bundesliga games on the bounce, scoring 18 and conceding just two in a run that also included a 6-0 drubbing of rivals Borussia Dortmund.
Recent form: WLWWWW
Recent form (all competitions): WWDWWW
Real are bidding to become the first side to win three straight Champions League crowns, having achieved a first back-to-back retention when beating Juventus in Cardiff last season.
In some corners this tournament is being portrayed as the final route Zidane has of proving his worth to the club's board after seemingly relinquishing La Liga to rivals Barcelona. A sacking in the summer would be harsh, but pulling off something remarkable in the Champions League would arguably paper over Real's shortcomings domestically this term.
Los Merengues travel to Germany having staved off a remarkable comeback from Juventus in the previous round. The Italian side were 3-0 up at the Santiago Bernabeu, before Cristiano Ronaldo rifled home a controversial penalty during injury time to send Real through.
The chilling efficiency on display in that spot kick perhaps serves as a condensation of Ronaldo's continued proficiency this term. The Portuguese forward has proven unstoppable of late. Having scored against Athletic Bilbao last time out, Ronaldo has scored in 12 games straight for Madrid, scoring 22 in the process.
Madrid have actually won the last five competitive matches between the teams and that will stand them in good stead going into the tie. The club have, however, conceded in 10 of their last 12 away matches in the Champions League, giving Bayern hope of taking something to Spain.
Midfield general Toni Kroos will be facing his former club having started his distinguished career at Bayern. The Germany international made 200 appearances for the Bundesliga club before moving to Spain.
Despite having the upper hand in the form tables in all competitions recently, Madrid have at times come unstuck in semi-final showings against Bayern. Wednesday will signal the seventh last-four meeting between the teams, Bayern winning won four to Madrid's two.
Real have had the tougher of ties in the knockout stages against Paris Saint-Germain and Juventus, and those victories might just stand Zidane's charges in slightly better stead ahead of a monumental European night at the Allianz.
Recent form: WWWDWD
Recent form (all competitions): WWDLWD
Heynckes rested most of his side in the Bundesliga at the weekend. Lewandowski will return to the starting XI up top, while Franck Ribery, Thomas Muller and Javi Martinez should all return in differing midfield and forward roles.
Madrid did not have a league game at the weekend and come into the contest well rested. Sergio Ramos should slot back into defence after missing out in the second game against Juventus through suspension.
Karim Benzema has found it tough going in front of goal of late and he will be pushed hard by Gareth Bale for a starting spot. Isco is likely to start ahead of Marco Asensio, while Nacho remains Zidane's only real injury concern.
Bayern Munich possible starting lineup:
Ulreich; Kimmich, Boateng, Hummels, Alaba; Rodriguez, Martinez, Alcantara; Muller, Lewandowski, Ribery
Real Madrid possible starting lineup:
Navas; Carvajal, Varane, Ramos, Marcelo; Modric, Casemiro, Kroos; Isco; Benzema, Ronaldo
Head To Head
Real Madrid made light work of Bayern when the clubs met last season in the quarter-final stages of the competition.
Real won 2-1 in Germany before producing another commanding display with a 4-2 win back in Madrid. Ronaldo was the standout again during those games, scoring five in the two ties, including a hat-trick in the second leg and both goals in the opener.
The Spanish side have actually beaten Bayern three times on the bounce at the Allianz. The teams have met 24 times in Europe, winning 11 each. During those contests there has been a total of 73 goals, 36 for Bayern and 37 for Real.
We say: Bayern Munich 2-2 Real Madrid
Bayern find themselves unbeaten at home this season and have scored at least five goals in five of their last eight matches at the Allianz. The Germans have had the easier route to the semi-finals, but they also have a coach with a proven track record in the latter stages of elite tournaments.
Madrid have won remarkable back-to-back titles in the Champions League and will fancy their chances of a third on the trot given the outlandish form of Ronaldo - the striker has seven goals in his last three games against Bayern.
Zidane might be slightly concerned given the second-leg showing against Juventus, but Madrid have more than enough individual quality to turn ties in their own favour at any given moment.