After 20-year-old former Barcelona trainee Icardi scored 11 league goals for Samp last season, Inter were quick to announce his imminent arrival at San Siro but the Ligurian club waited until today to endorse the move.
A statement published on Samp's official website read: "Sampdoria have allowed Mauro Emanuel Icardi to join Inter Milan on a co-ownership deal."
Samp also announced the signing of Italy striker Gabbiadini from champions Juventus on a co-ownership basis, after the Bianconeri bought out Atalanta's half of the 21-year-old's playing registration.
Gabbiadini told Sampdoria's official Twitter account: "Samp wanted to sign me at all costs. My team-mates have told me good things about the club, so I'm really happy."
Heading in the opposite direction is Simone Zaza. The 22-year-old striker has signed for the Bianconeri on a co-ownership deal but will play for Sassuolo in their maiden top-flight campaign.