The cause of death was complications from Alzheimer's disease, according to family spokesman Greg Purdy.
During World War II she sang with Grappelli and pianist George Shearing in a group that performed in London clubs throughout the Blitz. Toward the end of the war, she began singing with Glenn Miller's Army Air Force Band.
She made her American debut after the war, singing on Bob Hope's radio program. She later joined Frank Sinatra on the radio show "Your Hit Parade," which led to engagements with Goodman and other prominent orchestra leaders, including Vaughn Monroe and David Rose.
In the 1950s she formed a vocal quartet with Jane Russell, Connie Haines and Della Russell that recorded the hit gospel song "Do Lord." Rhonda Fleming later replaced Della Russell.
In 1974, Davis joined the cruise ship circuit, performing mostly on the Princess Line for the next three decades. During this time she continued to appear in nightclubs, singing standards such as "When the World Was Young," "Here's That Rainy Day" and "Baby Baby All the Time." In a 1975 review, Times music critic Leonard Feather wrote that she "reminds you of the days when nightclub singers of a certain special quality were called chanteuses."
Davis' 1948 marriage to Hollywood radio and television personality Peter Potter ended in divorce in 1965. Her companion of 35 years, Buck Stapleton, died in 2003. She is survived by three children, Bill Moore, Merry Moore and Melinda Moore Garber; a sister; and two grandchildren.
Funeral services will be held at 12:30 p.m. Friday at Forest Lawn Hollywood Hills.