Ajax shocked Europe when they eliminated champions Real Madrid in the previous round - while Ronaldo netted a hattrick in a historic turnaround against Atletico Madrid.
In a match-up with contrasting squads of youth vs experience, it's poised for a sensational two-legged European fixture against two former champions of the prestigious competition.
Juve boss Massimo Allegri confirmed the availability of five-time Ballon d'Or winner Ronaldo in the pre-match press conference after doubts were raised over his participation.
"Cristiano has trained with the team and is available," Allegri said, as per BBC Football.
Defender Daniele Rugani added: "Cristiano looks the same as ever. He's in good shape, a very important player for us, as everyone knows."
Confirmed starting XIs:
AFC Ajax: Onana, Veltman, De Ligt, Van de Beek, Neres, Tadic, Blind, Schone, De Jong, Ziyech, Tagliafico.
Juventus: Szczesny; Cancelo, Bonucci, Rugani, Alex Sandro; Bentancur, Pjanic, Matuidi; Bernardeschi, Mandzukic, Ronaldo.