MOSCOW, February 19 (RIA Novosti) - Natalia Bessmertnova, the legendary Soviet prima ballerina, has died at the age of 66, the Bolshoi theatre's press service said on Tuesday.

A press spokesman refused to reveal the cause of death, however, saying only that Bessmertnova had passed away "after a grave and long-term disease."

Bessmertnova was born in Moscow in 1941. Between 1961 and 1995 she was a prima ballerina at the Bolshoi Theater in the Russian capital.

One of her most memorable roles at the Bolshoi was as Giselle in the ballet of the same name. She was married to Yury Grigorovich, the former chief choreographer of Bolshoi.

Bessmertnova was a recipient of one of the Soviet Union's top state awards, the Lenin Prize. She was also a People's Artist of the U.S.S.R. She also received the Anna Pavlova prize in Paris.

Her surname is derived from the Russian word for 'immortal'. For ballet fans across the world, her memory is sure to live on.