Defending champion Real Madrid will face tough teams such as Borussia Dortmund and Sporting, while Barcelona has been drawn in the Group of Death.

Once the UEFA Champions League play-offs came to an end on Wednesday, the groups for the top club competition in the world were revealed on Thursday.

Defending champions Real Madrid were drawn in Group F, where they will face a tough challenge against Borussia Dortmund and Sporting Lisbon, in what will be an emotional return to Portugal for Cristiano Ronaldo.

On the other hand, Barcelona has been drawn in what some consider to be the "Group of Death" Los Blaugranas will have to battle against Pep Guardiola's Manchester City, Borussia Mönchengladbach and Celtic.

Last year's most surprising team, Leicester City, were drawn in a rather accesible group. Claudio Ranieri's men will want to keep the party going when they face Porto, Club Brugge and Kobenhavn

Perhaps the teams with the best luck were Bayer Leverkusen and Tottenham, which seem to be the frontrunners in Group E after being paired against Monaco and CSKA Moskva.

Here's how the groups will look like.

Group A: Paris Saint-Germain, Arsenal, FC Basel, Ludogorets

Group B: Benfica, Napoli, Dynamo Kyiv,  Besiktas

Group C: FC Barcelona, Manchester City, Borussia Mönchengladbach, Celtic

Group D: Bayern Munich, Atlético Madrid, PSV Eindhoven, FC Rostov

Group E: CSKA Moskva, Bayer Leverkusen, Tottenham, AS Monaco

Group F: Real Madrid, Borussia Dortmund, Sporting Lisbon, Legia Warszawa

Group G: Leicester City, Porto, Club Brugge, Kobenhavn

Group H: Juventus, Sevilla, Olympique Lyonnais, Dinamo Zagreb