The Italian champions have forked out €100 million (£88m/$117m) plus €12m (£10.5/$14m) in additional charges to secure the signature of the Portugal captain, who leaves Real as their all-time top scorer.
Newspapers around the world have been reacting, with Ronaldo's move front, rather than back, page news.
MARCA | There will be no other like him
Marca go with a striking front page, tallying up all Ronaldo's goals for Real with an amazing graphic.
The headline reads 'there will be no other like him'. Indeed.
AS | Goodbye Cristiano
A more straightforward headline from AS, though one that feels poignant following Ronaldo's departure.
'Goodbye Cristiano' is followed by 'It was nice while it lasted'. Ronaldo, as Real's all-time top scorer, is sure to agree.
Mundo Deportivo | CR7
Mundo Deportivo mock up Ronaldo in a Juventus shirt, with the headline 'CR7'.
SPORT | Shock Cristiano
This one is a little easier. A number of outlets have reacted to Ronaldo's departure with shock, and SPORT plaster that word on their front page.
A BOLA | CR7 Juve
A stark black and white background, an outline of Ronaldo's wonderful overhead kick goal against the club he has just joined, and the integration of the Juventus badge into the words CR7 and Juve. Artistic.
O JOGO | Serie A killer
Serie A killer! Ronaldo has enjoyed a healthy record against Italian opposition during his career, and Portuguese outlet O Jogo go with a pretty straightforward message, with the sub-heading 'Italian records in the sights of CR7'.
CORRIERE DELLO SPORT | Let there be light!
Corriere dello Sport go with a pun, with the words 'Fiat Lux' meaning 'let there be light' in Latin. But, of course, Juve are also owned by the FCA Group, who own FIAT, the car manufacturer.
TUTTOSPORT | There he is!
This one probably sums it up best in Italy... Tuttosport go remarkably simple with a headline of 'there he is'. How long will Juve be able to call on his talents?