AC Milan's Turkish midfielder Hakan Calhanoglu reacts during the Italian Serie A football match Lazio vs Ac Milan at Olympic stadium in Rome on April 26, 2021.
Hakan Calhanoglu was officially announced as an Inter player on Tuesday, completing his switch from neighbours AC Milan.
"The 27-year-old midfielder has signed a deal with the club lasting until 30 June 2024," said Inter Milan.
The German-born midfielder was a free agent after last season and wasted little time completing his move after Turkey were eliminated from Euro 2020 on Sunday.
Calhanoglu posted a picture of himself on social media on Tuesday evening wearing an Inter shirt, holding a can of blue paint and a brush and standing like a giant over the city of Milan.
An hour earlier, he had posted on Instagram a picture showing him in an AC Milan shirt with his back to the camera and the caption "thanks for everything AC Milan".
Inter won Serie A for the first time in more than a decade in May, but since then the club has been enveloped in uncertainty.
Calhanoglu is the first signing since the appointment of Simone Inzaghi to replace the departing coach Antonio Conte.
He strengthens Inter's midfield as they await medical decisions on the future of Christian Eriksen who suffered heart failure paying for Denmark at Euro 2020.
According to the Italian media, Calhanoglu will earn around 5 million euros (6 million dollars) a season at Inter, compared to the 2.5m euros he has earned at Milan.
AC Milan, who finished second for their best Serie A finish since 2012, also seem certain to lose another free agent, Italy goalkeeper Gianluigi Donnarumma, who is reported to be on the point of joining Paris Saint-Germain.
While direct transfers between the two Milan clubs are rare, Andrea Pirlo, Roberto Baggio, Clarence Seedorf, Zlatan Ibrahimovic, Mario Balotelli, Christian Vieri, Antonio Cassano and Christian Panucci are among those who have played for both clubs.
Inter pointed out that Calhanoglu follows fellow Turks, Hakan Sukur, Emre Belozoglu and Okan Buruk, who played for the club with varying degrees of success.