Andrea Agnelli, the Juve chairman, was at Ronaldo's hotel in Greece on Tuesday as discussions over the move advanced, Ronaldo's agent - Jorge Mendes - was believed to be simultaneously meeting with Real Madrid.
The move brings an end to a hugely successful nine-year spell in Spain, and takes him further away from a tax fraud case that may end up costing the Portugal forward more than $20 million in fines. I'm leaving but this shirt, this badge and the Santiago Bernabéu will always feel my own, wherever I am.
Ronaldo, who is Madrid's all-time leading goalscorer with 450 to his name, has won two La Liga titles, two Copa del Reys and four Champions League crowns during his time with the club.
"For any player it would be great to play with someone like Cristiano Ronaldo", he said.
Reports emerged a year ago that Ronaldo was again upset with the club's President Florentino Perez over a pay dispute and was intent on leaving, although he stayed on to lead the club to a third successive Champions League triumph.
After nine years at the Bernabeu, the Portuguese superstar is Italy-bound, as he will join the seven-time defending Serie A champions.
"It was very nice to be at Real Madrid", he said (h/t the Irish Independent).
"Real Madrid has conquered my heart and that of my family, and that is why more than ever I want to say thanks: thanks to the club, to the president, to the directors, to my friends, to all the coaches, doctors, physios, incredible workers that make everything function that are attending tirelessly to every detail".
Ronaldo, 33, joined Real from Manchester United in 2009 for a then-world record fee of £80million.
"These years at Real Madrid, and in the city of Madrid, have been possibly the happiest of my life".
Added to his five gongs, he is the only one who has won FIFA's The Best prize in the last two years, as well as the FIFA World Player of the Year (in England) and three UEFA Best Player awards.
He was the first player to score 100 Champions League goals and topped the competition's scoring charts six times.
Cristiano scored an incredible 451 goals in 438 games, meaning an average of 1.03 goals per game played for Los Blancos.