It was confirmed on Friday morning that the club had decided to part ways with Pirlo, despite the former Italy international winning two trophies in his debut season as manager of the team.
Allegri returns to the Old Lady after two years of unemployment and as one of the club's most successful managers in recent years.
The 53-year-old was first hired by the Italian giants in 2014, and won an incredible 11 trophies until his mutually agreed exit in 2019.

Nuno Espirito Santo (leaving Wolverhampton Wanderers)

Roy Hodgson (leaving Crystal Palace)

Ryan Mason (leaving Tottenham Hotspur)

Sam Allardyce (leaving West Bromwich Albion)

Hansi Flick (leaving Bayern Munich)

Marco Rose (leaving Borussia Monchengladbach)

Edin Terzic (leaving Borussia Dortmund)

Julian Nagelsmann (leaving RB Leipzig)

Hannes Wolf (leaving Bayer Leverkusen)

Adi Hutter (leaving Eintracht Frankfurt)

Paulo Fonseca (leaving Roma)

Claudio Ranieri (leaving Sampdoria)

Gennaro Gattuso (leaving Napoli)

Michel Der Zakarian (leaving Montpellier)

Rudi Garcia (leaving Olympique Lyon)