Ernesto Valverde names a strong starting XI as he welcomes last season's beaten finalists, with Dembele earning his full debut for the club following his £100m+ summer arrival from Borussia Dortmund.
Dembele's inclusion is just one change from the XI that hammered Espanyol 5-0 in the league on Saturday, with Gerard Deulofeu dropping down to the bench as a result.
Sergio Busquets, Ivan Rakitic and Iniesta continue to marshal the midfield, while Nelson Semedo, Gerard Pique, Samuel Umtiti and Jordi Alba make up an unchanged back four ahead of Marc-Andre ter Stegen between the posts.
Meanwhile, Juve boss Massimiliano Allegri makes six changes following the 3-0 victory at Chievo on Saturday, with Paulo Dybala returning to the frontline alongside Gonzalo Higuain and Douglas Costa as Mario Mandzukic misses out with a calf injury.
Gianluigi Buffon replaces Wojciech Szczesny between the sticks, while Mehdi Benatia is the only member of the back four to keep his place as Mattia De Sciglio, Andrea Barzagli and Alex Sandro come in for Stephan Lichtsteiner, Daniele Rugani and Kawdwo Asamoah.
Barcelona: Ter Stegen; Semedo, Pique, Umtiti, Alba; Busquets, Rakitic, Iniesta; Dembele, Suarez, Messi
Subs: Cillessen, Denis, Mascherano, Paulinho, Deulofeu, Paco Alcacer, Sergi Roberto, Andre Gomes
Juventus: Buffon; De Sciglio, Benatia, Barzagli, Sandro; Pjanic, Matuidi, Bentancur; Dybala, Douglas Costa, Higuain
Subs: Szczesny, Rugani, Asamoah, Sturaro, Merio, Caligara, Bernardeschi
Keep up with every twist and turn of the action at Nou Camp this evening with Sports Mole's live text commentary here.