Singleton guested in a large number of both comedies and dramas during her 30-plus career in television.
After performing as a featured dancer with the American Ballet Theater in her teens, the Brooklyn-born Dorthea Singleton began in showbiz as a vocalist with Art Jarrett's orchestra in the late 1930s. Her distinctive voice led to a career in radio, where she was an actress on "The Whistler" and other shows during WWII, performing at times with the likes of George Burns & Gracie Allens, Bob Hope and Jack Benny.
Singleton met Lucille Ball in the late 1940s during a performance of the radio show "My Favorite Husband"; a few years later, Ball invited Singleton to join the cast of TV's "I Love Lucy" as Carolyn Appleby. Singleton appeared on 10 episodes of the show from 1953 to 1957.
By the mid-1950s the actress was busy with TV guest appearances on programs including "Adventures of Superman," "The Loretta Young Show," "The Great Gildersleeve," "The Bob Hope Show" and "Alfred Hitchcock Presents."
Singleton also appeared in a few feature films during the 1950s: "Terror at Midnight," "Affair in Reno" and "Voice in the Mirror."
She was a series regular on the brief 1960 series "Angel," recurred on "My Three Sons" as Margaret Williams and guested on "The Munsters," "The Dick Van Dyke Show" and "Gomer Pyle, U.S.M.C." during the decade; she also returned to work with Ball on episodes of "The Lucy Show" and "Here's Lucy" as well as the 1980 telepic "Lucy Moves to NBC," and she made appearances on dramas including "Gunsmoke," "Twilight Zone," "The Fugitive" and "The F.B.I."
Her credits during the 1970s included "All in the Family," "Marcus Welby, M.D.," "Phyllis" and the daytime soap "Days of Our Lives." Singleton made one of her last appearances in a 1982 episode of "Dynasty."
Singleton also appeared as an interviewee in the "American Masters" documentary "Finding Lucy" in 2000 and in an "E! True Hollywood Story" episode devoted to "I Love Lucy" in 2005.
Singleton's husband Charles Isaacs, a comedy writer, director and producer to whom she was married for 61 years, died in 2002.