Ronaldo in Turin for Juventus unveiling

Cristiano Ronaldo and his girlfriend Georgina Rodriguez at Turin-Caselle Airport on Sunday

Cristiano Ronaldo was all smiles as he touched down in Turin on Sunday before completing his 112 million euro move ($A176 million) from Real Madrid.

The Portugal forward, 33, has agreed a four-year contract with the Serie A champions in one of the most dramatic moves in European football.

Ronaldo scored a record 451 goals over nine years at the Bernabeu, having signed from Manchester United and helping deliver four Champions League triumphs, three FIFA Club World Cups, two La Liga titles and two Copa del Rey trophies.

However, as the Spanish giants prepare for life under new head coach Julen Lopetegui, Ronaldo felt the time was right to move on, and in an open letter asked Real Madrid fans to understand his decision.

Juventus posted a short video clip of Ronaldo's arrival on a private jet, with the Portugal forward giving the thumbs up to photographers on the runway before being taken away in a club vehicle.

Ronaldo will be officially unveiled on Monday, with Juve calling a press conference for 6.30pm local time.

Earlier in the day he will undergo a medical before meeting his Bianconeri teammates and boss Massimiliano Allegri.

Juventus will pay 100 million euros ($A157m) to Madrid over two financial years and "additional costs" of 12 million euros ($A19m).

Last Tuesday's announcement that Ronaldo was headed to Turin set off a frenzy among Juve fans to buy team shirts with his No. 7.

Massive demand for the CR7 shirts caused the club's website to crash in the hours after news of the deal.