Real Madrid striker Alvaro Morata has joined Juventus for a fee of 20 million euros ($27.06 million), the Italian champions said on Saturday.

The 21-year-old striker signed a five year contract for Juventus after undergoing a medical although Real have included a buy-back clause in the contract.

"Morata has agreed a five-year contract with the club for a fee of 20 million euros, to be paid over three years," a statement from Juventus said.

"The deal includes the option for Real Madrid to reacquire the player's registration rights at the end of the 2015/16 or 2016/17 campaigns at predetermined values up to a maximum of 30 million euros.

"These values will be based on the number of matches played by Morata."

A highly-rated product of the Real youth academy, Morata came to the fore in the 2012-13 season, former coach Jose Mourinho's last at the club, but he was not able to maintain that progress last season.

"I am very happy to start a new adventure here. I am looking forward to starting right away," Morata told reporters on his arrival at Turin airport.

Meanwhile, another Real starlet, Casemiro, has moved out on loan to Porto for the upcoming season.

The 22-year-old defensive midfielder has arrived in Portugal to plug the gap left by fellow Brazilian Fernando who joined Manchester City last month.