She died in Los Angeles on Tuesday (26Jun12), according to trade publication Variety.
Perhaps best known for her role as neighbour Carolyn Appleby on Lucille Ball's hit U.S. sitcom, Singleton got her start in showbusiness as a dancer with the American Ballet Theatre, and later transitioned into radio, working with the legendary Bob Hope.
Her list of acting credits include guest spots on TV shows All in the Family, The Munsters, The Dick Van Dyke Show, The Twilight Zone, Days of Our Lives and Dynasty.
Singleton passed away on the same day as director/screenwriter Nora Ephron, and Lucille Ball's daughter, Lucie Arnaz, has since spoken of her sadness after losing two female visionaries in one day.
In a post on her Facebook.com page, Arnaz writes, "A day of saying hasta luego (goodbye) to two great ladies, Nora Ephron and Doris Singleton. May they both fly swiftly heavenward and enjoy a blissful rest for jobs well done down here. They were loved and appreciated and will be missed."