The Spaniard played a key role in helping the Blancos see off rivals Atletico Madrid in the semi-finals, scoring in the second leg at the Vicente Calderon.
However, with Bale returning to fitness ahead of the showdown, there was uncertainty over who Real boss Zinedine Zidane would opt for out of the two men.
But Zidane has decided to put his faith in Isco from the start with Wales ace Bale named amongst the substitutes in his home city Cardiff.
James Rodriguez, however, has not been included for the showpiece event, fuelling speculation over his future at Real.
Elsewhere, there are no surprises in Juventus' starting lineup as the Turin giants go in search of their third Champions League crown.
Gonzalo Higuain, Paulo Dybala and Mario Mandzukic all feature from the get go for Allegri's men.
Real are looking to become the first side in history to win the Champions League back-to-back, following their success over Atletico in the 2016 final.
Juventus, on the flip side, are looking to become only the second Italian side to ever win the treble, replicating Inter Milan's 2009/10 efforts under Jose Mourinho.
Real Madrid starting XI: Navas; Carvajal, Varane, Ramos, Marcelo; Modric, Casemiro, Kroos; Isco, Benzema, Ronaldo.
Real Madrid substitutes: Casilla, Nacho, Bale, Kovacic, Asensio, Morata, Danilo.
Juventus XI: Buffon; Barzagli, Bonucci, Chiellini, Alex Sandro; Khedira, Pjanic; Dani Alves, Dybala, Mandzukic; Higuain.
Juventus substitutes: Neto, Lichtsteiner, Benatia, Cuadrado, Marchisio, Lemina, Asamoah.