Iranian Princess Ashraf Pahlavi, the outspoken and glamorous twin sister of the country's deposed shah, has died at age 96.

Reza Pahlavi, a son of the late Shah Mohammad Reza Pahlavi, announced Princess Ashraf's death on Facebook on Thursday night, without offering a cause. A longtime adviser to Princess Ashraf in New York could not be immediately reached for comment Friday.

After her brother's 1979 overthrow in Iran's Islamic Revolution, Princess Ashraf shuttled between homes in Paris, New York and Monte Carlo. The French press dubbed her "La Panthere Noire," or the Black Panther. She published a memoir and remained outspoken immediately after the overthrow, but gradually faded from public view in later years.