She studied acting briefly under Michael Chekhov at Dartington, but when his school broke up with the outbreak of war, she then later went to America and worked as a personal assistant to Edward James.
He became President of Trinity College Players and in 1965 went with them to the Edinburgh Festival with a hugely successful late night revue directed by Max Stafford-Clark at the Traverse Theatre founded by Jim Haynes which had then only been going for two years.
Constantine joined the Royal Shakespeare Company under Trevor Nunn for the "Roman season" of Coriolanus, Julius Caesar, Antony and Cleopatra and Titus Andronicus.
He also appeared at the Royal Court Theatre in Keith Hack's production of The Good Woman of Szechuan with Janet Suzman, Ian McDiarmid and Jonathan Kent.
This in turn led to being asked to dialogue coach the TV mini-series Mussolini: The Untold Story with George C. Scott and many other stars, including the young Robert Downey, Jr. and Lee Grant.
A parallel career to acting stemmed from this when he was asked to dialogue coach on Bernardo Bertolucci's Oscar-winning film The Last Emperor (1987), in which he also played "The Oculist".