Juventus have decided their Maurizio Sarri experiment has not worked and for the second time in as many seasons the Bianconeri are on the hunt for a new head coach.
He has signed a two-year contract with the club, which runs until 30 June 2022.
A host of high-profile names were linked with the vacant position in Turin following Sarri's sacking earlier Saturday; the likes of Mauricio Pochettino, Zinedine Zidane, and Simone Inzaghi were all tipped as potential successors to Sarri, who was axed after winning the Serie A title in his lone season with the club.
The club which has dominated Italian football over the past decade said in a statement that Pirlo's appointment was a beginning of a new chapter.
"Today begins a new chapter of his career in the world of football, as it was said nearly a week ago: from Maestro to Mister", it added.
The playmaker, generally considered to be one of the best passers of a ball in the world during his peak years, was given his first managerial job by Juve just 10 days ago when he was appointed the club's Under-23 coach.
"Being a player and being a coach is really not the same thing at all".
He added: "We also believe he is destined for greatness".
Club legend Del Piero, who won the 2006 FIFA World Cup and 2011-12 Serie A title with Pirlo, said he is very happy for his ex-teammate even if he admitted his great surprise at the move.
Pirlo, who won 116 caps for Italy and is regarded as one of the finest players of his generation, retired in 2017 having spent two years in Major League Soccer at New York City FC after leaving Juventus.