To millions of TV viewers, Julia Hills is the man-hungry Rona in popular 1990s BBC sitcom 2point4 Children. To theatre audiences of late, she has again played a woman with love in her sights - this time in a darker, more disturbing role that continues to shock nearly 50 years after it was written.

In November, Hills has inhabited the world of Kath (pictured), the wonderful character created by Joe Orton in his breakthrough play Entertaining Mr Sloane. A black comedy fizzing with ideas about hypocrisy and aspiration, it was premiered just three years before Orton was murdered by his lover Kenneth Halliwell.

Reviews of this latest production at the Curve theatre in Leicester were mixed but critics have at least agreed that it is Hills at her best - The Stage, for example, called it a 'masterly performance'.

"I don't read reviews," Hills announces, taking the wind out of my sails when I suggest she might be pleased with the response.

Hills is sitting on the front row of the stalls, just yards from the space that Kath calls home. She warms up, thankfully, when dissecting Kath, a woman trapped in a 1960s East End house, living with her father and controlled by her sinister brother Ed (the excellent Andrew Dunn - remember Victoria Wood's dinnerladies?)

Kath mourns the baby she had to give up when younger, Hills says, but sees hope when the young Mr Sloane agrees to be her lodger. Feigning shock at his rude suggestions one moment and unzipping his trousers the next, it is a part associated with some of our best actresses, including Alison Steadman and Imelda Staunton.

"People have been surprised at the vulnerability of Kath. She's a victim of circumstances - a child trapped in a woman's body. She needs something to love. She had this love (her baby) when young and it was cut off. She was denied him, which is very traumatic of course.

"She's not been allowed to talk to people or mix with them, and when this beautiful young man walks into her life 25 years after giving up the child, it brings back all the hopes and dreams of her youth. This time she's going to be happy but, as we discover, she is seriously deranged."

Hills, who starred in 13 episodes of Andrew Marshall's sitcom Dad alongside George Cole, as well as clocking up 56 appearances as Rona throughout the 1990s, had no hesitation, she says, when director Paul Kerryson offered her the part. "The language attracted me first of all. The play leaves you feeling really uncomfortable because the language is so disturbing."

Sloane is a user but becomes used himself - shared in a bizarre pact sealed by Kath and her gay brother. They do the deal in the wake of their father's murder - beaten to death in a rage by Sloane who fears the old man will reveal his secret as the killer in a previous murder.

So how did Hills find the essence of Kath's character? "The rhythm of the play sounded as if it was the East End of London so that informed the voice. Then, like you do with any other good play, you look for the clues in the text."

In a career spanning more than 30 years, Hills has been luckier than most in getting her hands on good scripts. She is not someone who would get a tick in the 'household name' category but is nevertheless a face known to millions, whose work has been enjoyed in equal measure on television, radio and in the theatre.

Her breakthrough came in 1983 as a regular on Channel 4's Who Dares Wins... (pictured) - the first sketch show to be aired on the then brand-new station. Since then Hills has been nominated for an Olivier award for The Hired Man, has worked with the RSC, is a regular on Radio 4's The Archers and was cast in the original stage production of Calendar Girls. Fans of Outnumbered will remember her as the pushy mum of a chess-playing wizard.

As the interview comes to a close, the conversation drifts to women in comedy and I wonder if Hills has any inkling to revisit the sketch show format. After all, it's where she made her name and there is a dearth of good ones on the box right now. "I don't know of too many 55-year-old women in sketch shows, do you?"

Fair point. And with that, Hills gets up to go. There's another performance to give, and it's time for work.