Brazil left-back Alex Sandro has signed for Italian champions Juventus from Porto for £18.6m (26m euros) on a five-year deal.

The 24-year-old, with six caps for his country, has been linked with Manchester United  and Real Madrid  in the past.

Juventus begin their Serie A campaign at home against Udinese on Sunday.

They won the league and cup double last season but lost the Champions League final to Barcelona.