Liverpool have been drawn in Group B for this season's Champions League and will face the current European Champions, Real Madrid.
Liverpool and Real Madrid will face each other in Matchday 3 and Matchday 4 (updated LFC fixture list here).
The two European giants, with 15 European Cup titles between them, have met 3 times before - with Liverpool winning on all 3 occasions.
The reds won their third European Cup by beating Real Madrid in 1981, and knocked them out of the Champions League in 2009. The reds won 1-0 at the Bernabeu before dismantling them further at Anfield - registering a 4-0 win at Anfield.
Second seeds FC Basel have met Liverpool once before in the group stages.
The two sides met in the Champions League 12 years ago - drawing 1-1 at Anfield before a 3-3 draw in Switzerland. That 3-3 draw (which was 3-0 at half time to Basel) meant that Basel finished 2nd in the group and Liverpool were knocked out of the Champions League that year.
Ludogorets Razgrad are in the Champions League group stages for the first time. The Bulgarian champions began in the 2nd qualifying round in the middle of July.
They beat F91 Dudelange of Luxembourg 5-1 over two legs, then knocked out Partizan Belgrade on away goals (2-2).
In the play off round they overcame a 1-0 first leg deficit to Steaua Bucharest to head into penalties. With their goalkeeper having been sent off defender Cosmin Moţi scored his penalty before then saving two of Bucharest's efforts to send the Bulgarian's through.
Ludogorets also have a score to settle with FC Basel. Basel knocked Ludogorets out of last season's Champions League playoff 6-2 over two legs. FC Basel went in to the Champions League and Ludogorets went into the Europa League. They won 5 of their 6 group games to finish top. They then beat Lazio over two legs before being knocked out by Valencia.
LFC start their European campaign on the 16th September against Ludogorets Razgrad at Anfield. They finish against FC Basel also against Anfield [Click here for the updated LFC fixture list].
The reds have 4 home Premier League games following their Champions League clashes. Chelsea visit Anfield the weekend following Liverpool's trip to the Bernabeu and the reds travel to Old Trafford following the final group stage game - which will be on a Tuesday.
All the Champions League groups
Group A: Atletico Madrid, Juventus, Olympiakos, Malmo
Group B: Real Madrid, Basel, Liverpool, Ludogorets
Group C: Benfica, Zenit, Bayer Leverkusen, Monaco
Group D: Arsenal, Borussia Dortmund, Galatasaray, Anderlecht
Group: E: Bayern Munich, Manchester City, CSKA Moscow, Roma
Group F: Barcelona, Paris Saint-Germain, Ajax, APOEL
Group G: Chelsea, Schalke, Sporting, Maribor
Group H: FC Porto, Shakhtar Donetsk, Athletic Bilbao, BATE Borisov