SUE HOLDERNESS was very nearly the star that never was. Her character in Only Fools and Horses, Marlene, had played a key role as a running joke in the series for two years: yet she had never made an appearance.

The joke was that whenever her screen husband Boycie mentioned her, the rest of the cast would put in sly quips such as "Oh yes, we all remember Marlene", making her a classic ' 'er indoors' figure, never to be glimpsed by the viewing public.

However, that all changed in 1984 when Marlene eventually made an appearance.

Holderness said: "Everyone thought that Marlene should never appear because there was this joke about her. I thought my part was literally going to be one day's work where I was told just to run out to see David Jason, give him a passionate kiss, say a few lines, kiss him again and then go back inside.

"Since then it has become history and, well... a pension!"

John "Boycie" Challis said that bringing Marlene into the show was a dilemma not just for the writer, John Sullivan, but for those in charge of finding the right actress for the role.

Speaking prior to their appearance at the Theatre Royal Bath in Alan Ayckbourn's Time and Time Again, he said that Sue was definitely the right choice.

He said: "There was a lot of discussion about it, she was kind of an 'er indoors character, and I remember asking John (Sullivan) to put her in. It could still be a joke but with her in it.

"Then Sue came into the picture and came up with this wonderfully flirtatious, sort of minxy character which just suited the part perfectly."

Now, 18 years on, the two are happy to play up to what Holderness calls the 'Boycie and Marlene ticket', though she is quick to add that people banking on a comedy in the vein of Only Fools and Horses could well be disappointed.

She said: "It is a very different kind of comedy but I think the audience soon settles down to appreciate the play on its own terms."

Challis added that the duo's longstanding relationship has helped to make working together easier.

He said: "I think it is a lot easier if you know someone and you know how they work. Having been together on something for so long, we know what makes us laugh."

This year marks 31 years since the play was first performed. Regarded as one of Ayckbourn's best-loved comedies ("before everyone started committing suicide" remarked Holderness of the writer's subsequent work), it revolves around cricket, a congenial garden gnome and a sequence of incredible misunderstandings.

Whether that sounds like your cup or tea or you just want to see one of Britain's great comic duos in action, it is clear that the spirit of Only Fools and Horses is unlikely to ever desert the couple, a fact with which both are more than happy to live.

Holderness said: "Doing the show was a lot of fun. Some people would give their front teeth to get into a show like that with 23 million viewers watching every episode. I was proud to be part of it."

As for Challis, he said the show has been very important for him.

He said: "I should be so lucky to create something that means so much to people. It is a great privilege. There are a lot of great actors out there who never get that chance. And it has changed my life."

John Challis and Sue Holderness appear at the Theatre Royal Bath until Saturday 8 June.