Real paid tribute to Ronaldo in a lengthy statement on their website and said the player had asked to be transferred.
The 33-year-old and his world renowed agent Jorge Mendes met with Juventus' CEO on Wednesday to finalize the move to the club that has won the past seven Serie A titles.
That's because he and the rest of the Real Madrid team were offered their pick of club partner Audi's lineup last November and Ronaldo chose an 605 hp Audi RS7 for his one-year loan.
"Real Madrid will always be his home".
Ronaldo, whose Portugal were knocked out of the World Cup last 16 by Uruguay, hinted after May's Champions League victory against Liverpool that he was considering leaving the Santiago Bernabeu.
The signing of the latest Ballon d'Or victor and top scorer in the UCL for the last six seasons represents a major coup for Juventus, which has had a stranglehold on the Italian title since 2012 but has not won Europe's top prize since 1996.
Ronaldo, however, soured the celebrations immediately after the 3-1 win over Liverpool in the final in Kiev by indicating he had chose to leave, saying in a post-match interview "It was handsome to play for Real Madrid".
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Guests were served slices of christening cake, which is a tier taken from The Duke and Duchess of Cambridge's wedding cake. The Duchess of Cambridge wore a V-neck cream dress by Alexander McQueen and a floral embellished headpiece by Jane Taylor.
Ronaldo, a five-time Ballon d'Or victor, will now have the chance to win a European league title with a third club after completing a shock move to Turin.
"I think that the moment has arrived to start a new chapter in my life and therefore I have asked the club to accept letting me leave".
"He also became Real Madrid's all-time record goalscorer, with 451 goals in 438 games". The Portuguese worldwide also picked up two league titles and two Copa Del Ray crowns.
"In addition to the titles he won, Cristiano Ronaldo has been an example of dedication, work, responsibility, talent and determination", Madrid added.
Ronaldo will presumably feature in a two-man attack next to Argentina star Paulo Dybala, who naturally drops deeper in order to create chances for the Bianconeri, which could benefit the Los Blancos man. Ronaldo has been the competition's top scorer for the past six years, having had scored the most goals in a single campaign (17). "I came here to win titles".
Real are expected to receive a fee of €104m for the prolific Portuguese, with the player set to earn €30m per yeard for the duration of his four-year deal.
In beating the heavily-favored hosts France in the final, he broke yet another record - his three goals made him the first player to ever score in four European Championships.