Real captured a record-extending 14th European crown when they beat Liverpool in last season's final and, on paper, Carlo Ancelotti's side should have few problems in making the last 16 from Group F.
Barcelona striker Robert Lewandowski (34) will take on his former side in the group stage after the five-times champions were drawn with Bayern in Group C along with Inter and Viktoria Plzen.
Manchester City forward Erling Haaland will also face his former employers as the English champions were drawn in Group G with Borussia Dortmund. Sevilla and FC Copenhagen completed the group.
Qatari-owned Paris St Germain begin their quest for a maiden trophy in Europe's elite club competition in a tricky Group H with Juventus, Benfica and Maccabi Haifa.
Last season's runners-up Liverpool meet Ajax Amsterdam, Napoli and Rangers in Group A.
The Champions League group stage will begin earlier than usual on September 6th and conclude ahead of this year's World Cup finals which take place in Qatar from November 20th.
The knockout stages begin in February, with the final taking place in Istanbul's Ataturk Olympic Stadium in June.