Sussex-born actress Haydn Gwynne, best known for her roles in Peak Practice, Merseybeat and Drop The Dead Donkey, first visited Theatre Royal Brighton as a child with her godmother and brother.

They’d all go to the panto every year, but as she got a little older she was taken to see a comedy.

“It had Alastair Sim and Derek Fowlds of Basil Brush fame in it, and what could be more innocuous than that?” she explains from her London home.

“So we went to this Saturday matinee and there was a scene in the middle where Derek Fowlds started to take his clothes off.

“It was probably the early 1970s, and sure enough it ended up being a full-frontal nude scene with Derek Fowlds dancing round the stage.

“My godmother had her head in her hands and the din of seats flapping as the good older citizens of Brighton and Hove left the theatre in horror was noticeable.

“Of course, me and my brother were absolutely delighted.”

Forty years later, Gwynne, who decided to pursue an acting career after five years teaching in Rome in her 20s, is on the stage playing Stephanie Abrahams in Tom Kempinski’s award-winning play, Duet For One.

She has the challenge of bringing to the stage a story that echoes the life of Jacqueline du Pré.

Her character is a virtuoso concert violinist whose life is turned upside down when she is diagnosed with MS.

Gwynne’s most recent role before this part was as Queen Elizabeth opposite Kevin Spacey in Sam Mendes’ Old Vic production of Richard III, which toured the world and finished in New York.

Bizarre as it sounds, Gwynne sees similarities between the two parts.

“With Stephanie’s strength and her wit there is an overlap with Queen Elizabeth.

“Richard III was at a time when Queen Elizabeth has lost her children, who have been murdered, and her husband, who has been murdered. She has lost everything.

“She has a massive confrontation with Richard III. He wants to woo her daughter, one of her remaining alive children, and they go head-to-head. She almost intellectually bests him and is at the top level of her anger and sarcasm.”

As well as the overlap with Stephanie’s strength, vehemence and wit is the script.

“What is interesting coming from Shakespeare to this, in language terms, is Tom Kempinski has written it incredibly naturalistically. He has got the way we really talk, with ums and arghs, and you knows and stops in sentences, how we switch thought streams.”

She says it was a nightmare to learn. “I could have learnt Hamlet in a quarter of the time.”

Now she has it nailed, she hears similarities in everyday speech all the time. “It is very accurate. One person who saw the play said it felt like I was eavesdropping on this very private conversation.”

Opposite Gwynne in the two-person piece is William Gaunt. The actor who starred with Penelope Keith in BBC Television’s Next of Kin plays psychiatrist Dr Feldmann.

With only two in the cast, Gwynne is never off stage, which is a first for her.

It makes for a demanding role, especially given the sad story. Stephanie discovers her musical side is over because of MS and after the meetings with her shrink the rest of her life is gradually unpicked. Other events unfold that contribute to a complex emotional journey.

“It’s a big one to tackle. But though I am only a few weeks in, I am amazed it is not done more often.

“There’s not a huge representation of us women over a certain age, and so little classical theatre for us, I feel lucky that I’m getting to have a crack at it.”

She is keen to point out the weighty story is balanced.

“It sounds a heavy, big emotional journey, but it’s very entertaining.

“It’s a real rollercoaster that starts in one place and goes somewhere very explosive and the duel between two characters is funny. There are comedy chops as well.”

  • Theatre Royal Brighton, New Road, Monday, October 15 to Saturday, October 20. Starts at 7.45pm, matinees on Thursday and Saturday at 2.30pm. Tickets £12-£27. Call 0844 8717650