It was revealed earlier in the week that Llorente was close to sealing a move to Serie A, and now the Italian champions have confirmed Beppe Moratta's comments.
The Juventus deal will see Llorente stay at the Turin giants for four years.
"Juventus can confirm that Spanish international striker Fernando Llorente will join the club on July 1, 2013," reads a statement on the club's official website.
"The 27-year-old has agreed terms on a four-year deal and will move to Turin when his Athletic Bilbao contract expires at the end of the current season."
Llorente has scored seven goals in 21 international matches for Spain.