Stephenson had begun acting on television by 1972. She starred during 1973–74 as Julie King in the Australian TV series "Ryan". She made numerous television and film appearances, including as Michelle Osgood in the "" episode "Catacombs of the Moon" (1976), Josephine in the 1977 ABC production of Malcolm Williamson's opera "The Violins of Saint-Jacques", and Wendy in the 1977 "New Avengers" episode "Angels of Death". She had another recurring role as Iris Reade in the UK series "Funny Man" (1981). She made a TV comedy sketch show pilot, "Stephenson's Rocket", which was not taken up. Among her first appearances in the UK, she joined the live on-stage team at "The Comic Strip" led by Rik Mayall, Peter Richardson and Alexei Sayle at the Raymond Revuebar in Soho. This was not a happy experience, according to an interview she gave in 2014: "Doing stand-up was like a war with everyone playing this game of "I can be funnier than you".