Konstantin Mikhailovich Sergeyev (b. March 5, 1910 (February 20, Old Style) - April 1, 1992) was a Russian danseur, artistic director and choreographer for the Kirov Theatre. He was married to Natalia Dudinskaya, the theatre's prima ballerina. Galina Ulanova was his partner between 1930 and 1940. Sergeyev and Ulanova were the first to dance Romeo and Juliet in Sergey Prokofiev's ballet of the same name. Sergeyev was named a People's Artist of the USSR in 1957 and a Hero of Socialist Labor in 1991. He was the recipient of four Stalin Prizes.