The 31-year-old Brazilian forward returned to the San Siro after four years with Real Madrid on Monday and, after signing a two-year contract, he greeted hundreds of fans from the balcony of Milan's Via Turati headquarters.
A statement published on Milan's official website confirmed the 2007 Ballon d'Or winner - who reportedly returned to Italy on a free transfer - will meet the press at Milanello at 1100 BST on Thursday.
The Brazilian told the Milan Channel on his arrival at Linate airport: "Four years have passed and now I'm back.
"It's been two weeks that I thought if I could come back, a return to Milan would be ideal for me.
"In the last few days, I've been dreaming of hearing the fans sing my name in the San Siro again."
After leaving Sao Paolo as a teenager in 2003, Kaka won the Champions League and one Scudetto during his six years in Milan before moving to Real for a reported 70million euros in 2009.
He lifted the Primera Division trophy, the Copa del Rey and the Spanish Supercup with Real but steadily fell out of favour during Jose Mourinho's three-year spell as coach and announced his decision to leave the Bernabeu last week.