Stevens was born in Prestwich, England, and attended the Stand Grammar School. Before starting her television career she trained as a nurse at the Manchester Royal Infirmary. She was a regular on Play School and Playaway with Brian Cant and provided vocals for the Schools Television series Look and Read.
During the 1962-63 season she played Venus Smith, an occasional partner of John Steed in the TV series, The Avengers, alternating with Honor Blackman's Cathy Gale. Her character was a night club singer and each of her appearances included at least one musical number.