Wydad defeated defending champions Sundowns on penalties in a 2017 quarter-final and the Moroccans won at home and drew away at the group stage the following year.
Both sides won at home in the 2018/2019 edition and when they clashed again in the semi-finals, Wydad successfully defended a 2-1 first leg advantage to reach the final.
The Casablanca outfit then lost a controversial title decider against Esperance of Tunisia last May, storming off the field in the second leg after an equaliser was disallowed.
Wydad, Sundowns, 2015 runners-up USM Alger of Algeria and former semi-finalists Petro Atletico of Angola comprise Group C.
Seeking a third consecutive title, Esperance are in Group D with three former champions, Raja Casablanca of Morocco, JS Kabylie of Algeria and V Club of the Democratic Republic of Congo.
The title-holders were unimpressive in reaching the group stage, edging minnows Elect-Sport of Chad 3-2 on aggregate.
Record eight-time champions Al Ahly of Egypt will face former champions Etoile Sahel of Tunisia, twice runners-up Al Hilal of Sudan and Platinum of Zimbabwe in Group B.
Group A has five-time winners TP Mazembe of DR Congo, former semi-finalists Primeiro Agosto of Angola and Zesco United of Zambia, and Zamalek of Egypt or Generation Foot of Senegal.
The return match between Zamalek and Generation has been rearranged for October 24 after the Senegalese refused to play the second leg when the match date and venue were belatedly changed.
Whoever loses the delayed tie will drop to the second-tier CAF Confederation Cup and face ESAE of Benin in a play-off for a group place.
Champions League group participants are guaranteed S550,000 (500,000 euros) while the champions will become $2.5 million richer.
Primeiro Agosto (ANG), TP Mazembe (COD), Zamalek (EGY) or Generation Foot (SEN), Zesco Utd (ZAM)
Etoile Sahel (TUN), Al Hilal (SUD), Platinum (ZIM), Al Ahly (EGY)
USM Alger (ALG), Mamelodi Sundowns (RSA), Petro Atletico (ANG), Wydad Casablanca (MAR)
Raja Casablanca (MAR), JS Kabylie (ALG), V Club (COD), Esperance (TUN, holders)
Matchdays: Nov 29-30, Dec 6-7, Dec 27-28, Feb 14-15 2020, Feb 21-22, Mar 6-7
Note: Group winners and runners-up qualify for quarter-finals