In 2022, 57 years after playing the role on screen, she appeared as Vicki in a short webisode made to promote the release of her first season on Blu-ray.

[9] O'Brien moved to Ontario, Canada, in November 1969, with husband Michael Moulds, who was then head of the Canadian Film Institute.

She had recurring roles as Morgan in The Legend of King Arthur (1979) and as unit general manager Elizabeth Straker in the second season of Casualty (1987).

[17][18] She made guest appearances in The Duchess of Duke Street ("Trouble and Strife") (1976), Taggart ("Forbidden Fruit") (1994), Cracker ("The Big Crunch") (1994), A Touch of Frost ("Private Lives") (1999) and Heartbeat.

In 1974, she played Celia in "Panic", an episode of the BBC Radio series The World of Daphne du Maurier.