After drama school, Matheson began her career in 1967 with the Bristol Old Vic Theatre Company with which she toured the United States, including a season on Broadway, and Canada, followed by Europe and Israel, in three of Shakespeare's plays, the highlight of which was Sir Tyrone Guthrie's production of Measure for Measure. In 1971 she starred opposite Freddie Jones in Charles Wood's experimental drama The Emergence of Anthony Purdy esq. directed by Patrick Dromgoole for Harlech Television. It was chosen that year as ITV's entry in the Monte Carlo TV Festival though it was not widely networked. Nancy Banks-Smith, The Guardian's TV critic, said it was "largely incomprehensible to anyone east of Somerset". Her debut film The Chairman, starred Gregory Peck. She was chosen to star in the Spanish filmThe Exquisite Cadaver with Capucine, directed by Vicente Aranda, in 1969, which was showcased as the Spanish entry at the San Sebastian Film Festival. In the 1970s, she appeared in the Hammer Horror films Lust for a Vampire and Twins of Evil. Her other films include Pete Walker's The Flesh and Blood Show, The House that Vanished directed by Jose Larraz, Crucible of Terror, Confessions of a Window Cleaner, and Percy's Progress. Theatre work includes starring opposite Richard O'Sullivan in a British tour of the comedyBoeing-Boeing with Yootha Joyce and Sally Thomsett, Ray Cooney's Chase Me Comrade, Stage Struck by Simon Gray, Hugh and Margaret Williams’ The Flip Side, Funny Peculiar by Mike Stott, and Alan Ayckbourn's Bedroom Farce. In 1979, she undertook a season playing leading parts at the Donovan Maule Theatre in Nairobi, Kenya. When Matheson returned to London, she was invited to train as a continuity announcer for the new television franchise for ITV in the South Of England, Television South. She became a permanent continuity announcer for TVS in 1981. In 1990, she was part of the launch team for British Satellite Broadcasting, later to become BSkyB. She has also worked as a free-lance continuity announcer for Carlton Television and London Weekend Television. She does occasional narration & voice-overs, most recently in a monologue written by Martin Murphy, recorded for Bruised Sky Productions during lockdown in May 2020, and often attends film and television conventions and Hammer Film events as a guest. In 2017 Matheson took part, with fellow Hammer actress Caroline Munro, in a short spoof horror filmFrankula produced by The Misty Moon Film Society, of which she is an Honorary Patron. In 2019, she took part in a new documentary about Peter Cushing, ‘Peter Cushing In His Own Words’, talking about her work with him, released by the production company Rabbit & Snail Films. She also contributed to an American documentary about the actress Lynne Frederick: Lynne, the English Rose’ also released in 2019. As part of the 'special features' of the Studiocanal release of the Blu-ray of Hammer Films’ Lust For A Vampire she has recorded an interview about her work and in particular her experience of working on that film. She has returned to the big screen for a cameo in the feature film The Haunting of Margam Castle, starring Derren Nesbitt, Jane Merrow, and Caroline Munro, directed by Andrew Jones for North Bank Entertainment, due for release in 2020. Most recently Matheson has undertaken the narration for "Mary Millington On Location", part of the special features for the new Mary Millington box set, which is due to be released by Screenbound Entertainment in 2020.
