While playing for the two biggest clubs in a city is considered sacrilege in most parts of the world, that's never really applied to Milan.
Not only are moves between the two clubs rather commonplace, a number of the game's greats have turned out in Milan's black and red and Inter's black and blue.
Below, we look at the players to have represented both sides of Milan.
Having played for the biggest club in the Netherlands and the biggest club in Spain, Clarence Seedorf would go on to represent two of the biggest clubs in Italy.
After spending two years with Inter, Seedorf moved across the City to play in black and red where he'd arguably spend the best years of his career.
After moving from Brescia to Inter, there was little evidence to suggest Andrea Pirlo would go on to become one of the game's great midfielders. After two loan spells with Reggina and Brescia, Pirlo made the switch to Milan, where he carved out a niche as a deep-lying playmaker, winning the UEFA Champions League and Serie A twice.
After four years with Milan, Hakan Calhanoglu left at the expiry of his contract to move to Inter where he won a first Serie A title in 2024, the year after reaching the UEFA Champions League final.
Since swapping red for blue, the Turkish international his taken his game to another level, twice being named in the Serie A Team of the Year and being named Serie A's Best Midfielder for 2023/24.
Perhaps the city's most famous dual-representative, Zlatan Ibrahimovic spent three successful years with Inter, winning Serie A in all three seasons before moving to Barcelona.
The move to Spain didn't work with Ibrahimovic joining Milan for two years, winning two more league titles.
After more than seven years away, Ibrahimovic returns to Milan, spending four more seasons at the San Siro.
Not quite as high-profile as some of the other players on this list, Matteo Darmian only made a handful of appearances for Milan in his early days before joining Inter in 2020, winning Serie A and reaching the UEFA Champions League final.
One of the best strikers of his generation, Christian Vieri's move from Lazio to Inter broke the world transfer record in 1999.
Despite six years with Inter, Vieri only ever won one trophy with the Nerazzurri and had a brief stint with Milan at the end of his time with Inter, playing for 10 Italian clubs in total.
Despite being one of the best #10s to ever play the game, Roberto Baggio frequently found himself on the move throughout the latter years of his career. Baggio spent five years at Fiorentina and five years at Juventus before moving to Milan in 1995.
Baggio spent two years with Milan before moving to Bologna for a year, then back to the San Siro to join Inter in 1998, uniting with the great Ronaldo.
A complete striker, Hernan Crespo made his name with Parma before moving to Lazio in 2000. Two years later, Crespo was on the move again, joining Inter, where he'd spent a year before being snapped up by Chelsea.
Following the arrival of Jose Mourinho at Chelsea, Crespo was sent back to Milan on loan, joining the Rossoneri, where he'd score twice in UEFA Champions League final, only to lose on penalties to Liverpool.
Though they appeared to be two totally different players, it was indeed the same Ronaldo who turned out for Inter and Milan. Moving to Inter as the world's best player, Ronaldo's time at Inter was plagued by injury.
After a 25-goal maiden campaign, Ronaldo was restricted to just 36 league appearances in the next four years.
The Brazilian would return to Italy after four-and-a-half years with Real Madrid, joining Milan, but with his powers greatly waning, Ronaldo left after just 20 appearances in red and black.
Dario Šimić
Sulley Muntari
Thomas Helveg
Giuseppe Favalli
Mario Balotelli
Christian Panucci
Cristian Brocchi
Giampaolo Pazzini
Maurizio Ganz
Andrea Poli
Aldo Serena
Gloria Marinelli
Lisa Alborghetti
Andrés Guglielminpietro
Francesco Acerbi
Francesco Coco
Patrick Vieira
Antonio Cassano
Taribo West
Leonardo Bonucci
Edgar Davids
Mancini
Domenico Morfeo
Pierluigi Orlandini
Raoul Bellanova
Matías Silvestre
Alessia Piazza
Lavinia Tornaghi