The show, which runs through to January 28, 2018, features more than 25 costumes spanning almost 100 years.
The creations on display include several by fashion designers such as Karl Lagerfeld and Gianni Versace, as well as costumes worn by opera divas Maria Callas and Renata Tebaldi and dance legend Rudolf Nureyev.
The Friends of La Scala Association organised the show, following a restoration of the costumes.
In doing so, the association is celebrating its 40th anniversary in collaboration with the City of Milan, the Palazzo Reale, and La Scala opera house.
“The costumes tell the story of the role that La Scala has had as an experimental research centre,” Milan Culture Councillor Filippo Del Corno said.
“It’s also the story of how the work was directed, by highlighting the extraordinary artisanal quality of the opera house’s workshops,” he said.
The oldest costume on display is that of Isabella in Rossini’s L’Italiana in Algieri, which was created by Caramba (Luigi Sapelli) in 1933.
Works by famous fashion designers include Karl Lagerfeld’s costume for Luca Ronconi’s opera The Trojans and Gianni Versace’s Salome costume for the opera staged by Robert Wilson.
Other costumes in the show include one created by director Franco Zeffirelli for Maria Callas as Donna Fiorilla in Rossini’s Il Turco in Italia in 1955, which Zeffirelli himself directed.
Ballet costumes include the prince costume worn by Rudolf Nureyev in a 1969 production of The Nutcracker and the red dress designed by Luisa Spinatelli in 1987 for Carla Fracci’s performance in La Fille Mal Gardee.
The most recent costumes showcased are by Maurizio Millenotti for the stepmother and stepsisters in the 2015 production of Cinderella, directed by Mauro Bigonzetti.