Benzema's inclusion means that Alvaro Morata drops down to the bench, while Raphael Varane partners Sergio Ramos in the heart of defence, as Madrid start their journey to become the first side to ever retain the Champions League crown, 109 days after winning it with victory over rivals Atletico Madrid in Milan.
Zinedine Zidane is without the likes of Keylor Navas, Isco and Fabio Coentrao in his matchday squad, but the headline news is that Ronaldo - who spent seven years at Sporting - will feature from the off at the Bernabeu.
Liverpool loanee Lazar Markovic is among the visitors' subs, while summer recruit Bas Dost is handed just a second start since joining the side as they aim to carry over their 13-match winning run in the Portuguese top flight onto the European stage.
Real Madrid: Casilla; Carvajal, Ramos, Varane, Marcelo; Modric, Casemiro, Kroos; Bale, Benzema, Ronaldo
Subs: Yanez, Pepe, James, Kovacic, Lucas Vazquez, Morata, Danilo
Sporting Lisbon: Rui Patrício; Joao Pereira, Coates, Semedo, Marvin; Carvalho, Adrien; Gelson, Bruno Cesar, Ruiz; Dost
Subs: Beto, Schelotto, Markovic, Campbell, Oliveira, Andre, Elias
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