The French striker has officially left Chelsea after making 119 appearances and scoring 39 goals since January 2018 and has signed a two-year deal with the Italian giants worth £1 million.
The 34-year-old sportsman will also receive an additional £1 million in bonuses, subject to making a specific number of appearances and the club qualifying for the Champions League.
Giroud - who will wear the number 9 shirt for his new club - completed his medical at Milan's La Madonnina clinic on Friday (16.07.21) morning.
And the sportsman later took to Twitter to thank all at Chelsea for the "special moments" he's enjoyed during his stint with the London club, including winning the winning the Champions League, Europa League and FA Cup, and admitted he's looking forward to embarking on a "new journey" now.
He wrote: "To all the Blues, to my team-mates, to all my coaches, to the whole club, a huge thank you for these special moments,' he wrote.
"I'm starting a new journey with a light and happy heart. Our victories in FA Cup, Europa League and Champions League have been magnificent."
Giroud joined Chelsea from Arsenal for £18 million in January 2018, six years after he first moved to the Premier League from Montpellier in his native France. The Gunners paid £10.8 million for him at the time.