Barbara Sinatra, the wife of the late great singer Frank Sinatra, died on Tuesday morning at her home in Rancho Mirage, California. She was 90.

According to John Thoresen, director of the Barbara Sinatra Children's Center, Sinatra died of natural causes "comfortably surrounded by family and friends".

Barbara was from Bosworth, Missouri and began her modeling career at the age of 18 after her family moved to Long Beach, California.

Shortly after the move, she married Robert Oliver, later divorced and then married Zeppo Marx in 1959. After she and Marx divorced, she would marry Frank Sinatra, who himself was previously married three times.

Barbara and Frank wed in 1976 in a private ceremony at the Annenberg Estage in Rancho Mirage. They remained married until Frank's death in 1998.

Barbara Sinatra would become famous in her own right as she founded the Barbara Sinatra Children's Center to help children who were victims of abuse.

She is survived by her son Robert Oliver Marx, his wife Hillary Roberts and granddaughter Carina Blakely Marx.