Alice and Ellen Kessler, German twin sisters whose singing and dancing talents made them famous across Europe in the 1950s and '60s, died by joint assisted suicide on Monday, according to the German Society for Humane Dying.

They were 89.

"They had been considering this option for some time. They had been members of the organization for over a year. A lawyer and a doctor conducted preliminary discussions with them," the organization said in an English-language statement.

"People who choose this option in Germany must be absolutely clear-headed, meaning free and responsible," the organization added. "The decision must be thoughtful and consistent, meaning made over a long period of time and not impulsive."

Germany's highest court overturned a ban on medically assisted suicide in 2020, ruling that the previous law infringed on constitutional rights.

Alice and Ellen Kessler were born on Aug. 20, 1936, in Nazi Germany, where they trained as ballet dancers. In the early 1950s, their family fled from East Germany to West Germany, where they launched their professional entertainment careers.

The Kessler Twins, as they were professionally known, delighted audiences around the world with their spirited performances. They reached the pinnacle of their celebrity in postwar Germany and Italy, though they also found fans in the United States.

In early February 1963, the Kesslers made their American television debut on the CBS variety show "The Red Skelton Hour," delivering a song-and-dance version of "Les Girls." The same month, they appeared on the cover of Life magazine.

"SENSATIONS FROM GERMANY: KESSLER TWINS," Life's cover headline blared.

They also performed on CBS' "The Ed Sullivan Show." In a post on Instagram by a account dedicated to the show's legacy, the Kesslers were hailed as "dazzling stars, true legends, and sisters whose grace, charm, and magic will shine forever."

The two women moved to Italy in the '60s and posed on the cover of the Italian edition of Playboy. They acted in various European film productions throughout the decade and briefly appeared in the Hollywood biblical epic "Sodom and Gomorrah."

The sisters ultimately moved back to Germany in the '80s, settling in a home near Munich. They never married.

They were given honorary awards from the German and Italian governments for their contributions to the entertainment industry, including the Order of Merit of the Federal Republic of Germany in 1987.

If you or someone you know is in crisis, call 988 to reach the Suicide and Crisis Lifeline. You can also call the network, previously known as the National Suicide Prevention Lifeline, at 800-273-8255, text HOME to 741741 or visit SpeakingOfSuicide.com/resources for additional resources.