She is best known for playing Marlene Only Fools and Horses, and the recent spin-off, The Green Green Grass, but Sue Holderness has more strings to her bow.

She says dancing with Wayne Sleep in Sleeping Beauty is one of the best things she has done.

"As soon as I knew we would be working together, I said that I am jolly well going to dance with Wayne. It's the highlight of my career, I tell you, I look forward to that moment on stage more than anything else."

Unlike Marlene, she is extremely well spoken, but in no way intimidating. Instead she is utterly charming, with a great wit. She says singing and dancing are skills she has, but has not used for some time.

"I was a bit of a dance, ballet, tap, and modern girl from the age of three, but dancing was never going to be my life."

Her versatility has been most evident in the past couple of years with pantomime and roles with John Challis in more serious work. But she has made a name for herself by making people laugh.

"When I was at drama school, I thought I would be the next serious Shakespearian heroine of our time. But I was doing a Chekhov play, and I thought I was being terribly moving. My best friend's father said You were wonderful, but you are definitely going to make your name in comedy', which I wasn't sure how to take. But he proved to be right."

Marlene has defined her career, but it was something of a happy accident that she became a main part in the series Only Fools and Horses.

"The director had seen me in a show called End of Part One, and he just offered me the job. It was just for one morning. I had a very funny little scene with a dog and Del Boy. Fortunately the writers liked it, and the rest as they say is history.

"The shock really was getting the Green Green Grass as a spin off, and getting a career break at this age is very exciting indeed."

Having played Marlene for so many years, she jokes that they are virtually one and the same.

"Oh I've turned into her now, it's awful. When I go shopping I buy leopard skin and high heels that are really uncomfortable. I don't know when one stops and the other starts."

In The Green Green Grass she reprises her role opposite John Challis (Boycey) a partnership which has endured on television and stage.

"It's lucky we get on. We are like a tired old married couple. We bicker. We are filthily rude to each other, and love each other to death."

Last year they played opposite each other in a Neil Simon's London Suite, characters a world apart from Mr and Mrs Boyce.

"The play was quite touching. John's character was dying of cancer. It was a very emotional play."

Sue is very familiar with the Theatre Royal in Windsor, not least because of her relationship with the theatre director, Mark Piper. The couple live in the area. "The great thing is, if you marry the director you tend to get more parts. It wasn't a conscious decision, but it has worked rather well. People say what advice could you give young actors?' Marry the director. That's the answer."

She is rediscovering a form of theatre she has little recent experience with.

"I hadn't done panto for 26 years until last year when I was asked to play the Wicked Queen at Aylesbury. Now that I have the bit between my teeth, I want to be the Wicked Witch all year round."

She seems too vibrant to be landed with the title "national institution", but Sue Holderness is certainly a treasure. She is said to steal the show as the Wicked Witch, but you can also catch her in the The Green Green Grass on BBC1 during Christmas.

Beauty and the Beast, Theatre Royal Windsor, until January 8. Tickets: 01753 853888.