PRAGUE (AP) — Vlado Milunić, a Czech architect of Croatian ancestry who co-designed Prague’s iconic Dancing House building together with his colleague Frank Gehry, has died at 81.

Czech public radio announced his death on Sunday and said it was confirmed by his family. No details were given. He was battling an unspecified serious illness.

The Dancing House is an unusual building that resembles a pair of dancers; It’s is a rare example of top contemporary architecture in Prague, which otherwise abounds with picturesque historical buildings, churches and monuments.

Due to its shape, the building is also known as Ginger and Fred after famed dancers Fred Astaire and Ginger Rogers. It’s formed by two central towers; the one known as Ginger is made of glass and steel, while Fred has a concrete body and a metal head.

It's located on the bank of the Vltava River next to the building where the late President Vaclav Havel used to live. It was built on a plot of land that earlier housed a 19th-century neo-Renaissance building that was destroyed in a World War II air bombardment.

Havel is said to have been the first who talked to Milunić about making an architectural study for a possible arts center on the plot. In 1992, the Dutch company Nationale Nederlanden acquired it, seeking to build an office building ,and Milunić approached Gehry to participate. He agreed.

Their nine-story project was completed in 1996 and was named among “The Best Design of 1996” by Time magazine.

The unusual architecture initially caused some controversy, with critics saying it didn’t fit its historical surroundings. But such arguments gradually disappeared and the building became a must-seen site for tourists alongside Prague's historical landmarks like the Charles Bridge and Prague Castle.

Born on March 3, 1941, in Zagreb, Milunić lived in Prague with his family since he was 16. He studied architecture at the Czech Technical University where he later became a lecturer. In the late 1960s, he spent three years in Paris on internships.

Among his other projects, the architect is known for an apartment complex and several retirement homes in the Czech capital as well as well a day-care center for disabled children in the city of Ceske Budejovice.