BERLIN — Alice and Ellen Kessler, twin dancers and singers who launched their career in the 1950s and performed with Fred Astaire, Frank Sinatra and Harry Belafonte among others, have died, police in Germany said Tuesday. They were 89.

The death of the twins in Grünwald, a prosperous suburb of Munich where they shared a house, was reported by German newspaper Bild and news agency dpa on Monday, without named sources. Munich police on Tuesday confirmed the deaths, saying in an emailed statement that it was a “joint suicide.”

The Kessler twins learned to dance at a young age and joined the Leipzig Opera children’s ballet. In 1952, when they were 16, their family fled to West Germany, where they danced in a revue theater in Düsseldorf. In 1955, the sisters were discovered by the director of the Lido cabaret theater in Paris, where their international career took off.

In the 1960s, the Kessler twins toured worldwide, moved to Rome and performed with Astaire, Sinatra and Belafonte. They turned down an offer to appear with Elvis Presley in “Viva Las Vegas” in 1964 for fear of becoming defined by musical films in America, dpa reported.

Even at 80, the sisters appeared on stage in a musical. Alice said shortly before their 80th birthday that they probably wouldn’t have managed to perform for so long alone.

Being a twosome “only has advantages,” she said. “Together you’re stronger.”

Asked about the secret of their success, she remarked: “Discipline, every day. Gratitude, time and again. Humility, not cockiness. And togetherness. Until death.”