Chelsea handed trips to Germany and Athens in Conference League
The Stamford Bridge side are playing in the Conference League for the first time in their history after finishing sixth in last season's Premier League.
They will play home games against Gent of Belgium, Shamrock Rovers of Ireland and FC Noah of Armenia, who came through four qualifying ties to reach the league stage.
Enzo Maresca's Chelsea will go to Heidenheim, who qualified after finishing eighth last season in their first-ever German Bundesliga campaign.
Chelsea will also visit former European Cup runners-up Panathinaikos and Astana of Kazakhstan.
The London side, who scraped past Servette of Switzerland in the play-offs, will be hoping to add the Conference League to a trophy cabinet which already contains two Champions Leagues, two Europa Leagues, two Cup Winners' Cups and two UEFA Super Cups.
The Conference League was only created three years ago but is being shaken up this season along the same lines of the other two European competitions.
The group stage has been replaced by a league phase in which all 36 clubs are pooled together.
Participants are then split into six seeded pots, with every team facing one club from each pot for a total of six matches - rather than the eight games per club in the Champions League and Europa League.
Runners-up in each of the last two years, including to Olympiakos in last season's final, Fiorentina of Italy are once again involved.
Their opponents include The New Saints, who are the first club from the Welsh league system to feature at this stage of a European competition.
Real Betis will be the Spanish representative, while no French team features in the league phase after Lens lost to Panathinaikos in the playoffs.
Hearts of Scotland will notably take on FC Copenhagen and Cercle Brugge away, and Heidenheim at home.
Larne, the first club from the Northern Irish league to reach this stage of a European competition, will host Shamrock Rovers from across the border. The latter will also take on The New Saints.
UEFA will reveal specific fixture dates on Saturday, but the first matches will take place on October 3rd and the final matchday is scheduled for December 19th.
This season's Conference League final will be held in Wroclaw, Poland on May 28th, next year.