Alexander Godunov, the swashbuckling Russian ballet dancer and movie actor, was found dead yesterday at his home in West Hollywood, Calif. He was 45.

Sheriff's Sgt. Bob Minutello told The Associated Press that paramedics called to Mr. Godunov's home found him dead shortly before noon, and that his death was described by his physician as of natural causes. It was not immediately known when he had died. Mr. Godunov was discovered by a nurse who had not heard from him since May 8 and decided to investigate.

Tall and dramatic, with long blond hair that flared behind him during his soaring jumps and whiplash turns, Mr. Godunov was an instant star wherever he danced. A joyful but undisciplined virtuoso dancer, he was capable of stunning feats. There were times when acting a character seemed to bore him. But he was the sizzlingly sexy center of attention whenever he performed.

Mr. Godunov joined the Bolshoi Ballet in 1971, as its youngest principal dancer, and was chosen by the legendary prima ballerina Maya Plisetskaya to be her partner soon after. In 1973, audiences -- and dancers -- took to him immediately when he toured the United States with the Bolshoi. Cynthia Gregory, a leading ballerina of American Ballet Theater, said later that she wished he would defect from the Soviet Union and become her partner.

In August 1979, Mr. Godunov did defect while on tour with the Bolshoi in New York. Rudolf Nureyev, Natalia Makarova and Mikhail Baryshnikov had defected before him, but Mr. Godunov was the first from the Bolshoi. His defection was front-page news around the world, and became even bigger news a few days later when Lyudmila Vlasova, a Bolshoi soloist to whom he was married, tried to return to the Soviet Union. It was only after an airport standoff of many hours that she was able to convince American authorities that she was not returning under duress.

A few months after his defection, Mr. Godunov joined Ballet Theater. He performed with it until 1982, when he was let go by Mikhail Baryshnikov, artistic director of the company. The official reason for his dismissal was that Mr. Godunov would not have sufficient roles because of changes in the repertory. He was then the companion of the film actress Jacqueline Bisset, and he embarked on his own film career after a short tour with an ensemble called Godunov & Stars.

Mr. Godunov's first movie role was in "Witness," with Harrison Ford and Kelly McGillis in 1985. In a review in The New York Times, Vincent Canby described Mr. Godunov, who played an Amish farmer, as the film's "most riveting presence." "Mr. Godunov displays a kind of quiet, amused self-assurance that effectively steals every scene he's in," Mr. Canby wrote.

For a time, soon after joining Ballet Theater, Mr. Godunov had disappointed some critics and audiences by attempting to tone down his natural flamboyance. A former colleague at Ballet Theater described him yesterday as an innocent in an unfamiliar world. And after his success in "Witness," he failed to have a similar impact in his other films, which included "Die Hard" (1989).

Boris Alexander Godunov was born on Sakhalin Island, and began studying dance at 9 at the Riga State Ballet School, where his mother enrolled him to prevent him from becoming "a hooligan," as he later put it. Mr. Baryshnikov was one of his classmates. On his graduation, Mr. Godunov joined Igor Moiseyev's Young Ballet and toured with that company.

He talked his way into the Bolshoi by appealing to Yuri Grigorovich, its director, and soon after he joined, he danced Prince Siegfried, the lead male role of "Swan Lake," and won many rave reviews. Leading roles followed in "Giselle" and other classics as well as in contemporary ballets by Alberto Alonso, Roland Petit and Miss Plisetskaya. He won a gold medal at the Moscow International Competition in 1973.

Always a stubborn individualist, Mr. Godunov was marked as a troublemaker and potential defector on his return from the 1973 tour because of his outspoken admiration for American culture. After a 1974 tour with Miss Plisetskaya, he was not allowed to leave the Soviet Union again until 1979 and rarely danced during that period.

Mr. Godunov danced lead roles at Ballet Theater in works that included "Giselle," "Swan Lake," "Raymonda," "La Bayadere" and "Don Quixote," as well as Mr. Petit's "Carmen" and Jose Limon's "Moor's Pavane." In 1981, he appeared with the Alvin Ailey American Dance Theater in a razzle-dazzle duet choreographed by Mr. Ailey for him and Judith Jamison.

After his dismissal from Ballet Theater, Mr. Godunov also performed with the Asami Maki Ballet of Japan, the Israel Ballet and Maurice Bejart's Ballet of the Twentieth Century. He studied acting with Stella Adler and took voice lessons at the Juilliard School of Music in preparation, it was said, for a film career.

His other films included "Money Pit" (1986) and "North" (1994).

Mr. Godunov became an American citizen in 1987.

His marriage ended in divorce in 1982.

Alexander B Godunov