Born Ruby Bernadette Nanette Theresa Fabares, she began performing professionally at age five, and soon was working with Ben Turpin in vaudeville. She was featured as Baby Nan in several "Our Gang" comedy shorts in 1927, when she was seven. In her late teens she appeared in two Hollywood films, beginning with The Private Lives of Elizabeth and Essex (1939); during the subsequent decades she went on to appear in only a few more films, most notably the musical The Band Wagon (1953) in which she performed with Fred Astaire and Jack Buchanan in the famous "Triplets" number. She costarred with Sid Caesar on the TV series Caesar's Hour. She is best known as a Broadway musical comedy star. She is the widow of screenwriter Ranald MacDougall, and she is the aunt of actress Shelley Fabares.