Brazilian left-back Alex Sandro has snubbed reported interest from Manchester United and Real Madrid to sign for Juventus from FC Porto, the Italian champions confirmed on Thursday.

The 24-year-old Brazil international joins the Turin giants on a five-year deal for 26 million euros ($29.1m, £18.6m), to be paid over three years.

A statement from Juventus said: "Juventus Football Club can today confirm that Alex Sandro has completed a permanent switch from Porto for a fee of 26 million euros, to be paid over the next three years.

"The 24-year-old has signed a five-year contract with the club."

Juventus, who won the league and Cup double last season but lost to Barcelona in the final of the Champions League, open the new Serie A season at home to Udinese on Sunday.

The first major challenge of the season for Massimiliano Allegri's men is their away trip to title pretenders Roma, who finished distant runners-up last season, on August 30.