Like 20 million other English people, Caroline Quentin knows exactly where she was on the night of 4 July 1990. As England played their World Cup semi-final against Germany, the actress was in Majorca, in a hotel room full of English comedians watching the event on television.

'I was bored out of my mind,' she recalls. 'The only thing I remember enjoying was a ritual the boys invented whereby after England scored their first penalty, for the second everyone had to do exactly what they were doing for the first. They seemed seriously to believe that our actions in front of the telly in Majorca could really influence events in Turin. Pathetic. Fortunately what I was doing when the first penalty was scored was drinking a pina colada.'

It was an evening Caroline assumed she would easily forget. Instead, it has dominated her working life. Even as the triumphant German footballers were sitting on a beach somewhere dreaming of renegotiated contracts, Arthur Smith and Chris England, two of her television-watching companions that night, were converting the whole episode into a stage play, An Evening With Gary Lineker. And they invited her to take the lead role.

'We threw it together, rehearsed it in four days and put it on at the Edinburgh Festival,' she says. 'I was in another play immediately before it, said my last line in that, dashed by taxi across to do Lineker. I walked on stage, delivered my first line and off it went. Whoosh.'

Whoosh indeed: awards were bestowed upon it, a seven-month run in the West End ensued and next Tuesday, with the England team poised for another World Cup (except this time they will be the comedians in front of the telly), it is to be screened on ITV. Caroline reprises her stage role and, playing himself, is Gary Lineker; better casting than in Edinburgh, when the role was on one occasion taken by the comedian Paul Merton, a man not renowned as a Lineker lookalike.

'We used to grab any passing friend who was free and put them in football shorts,' Caroline remembers. 'One night it was Paul.'

They had met on the train on the way to the festival. 'I was sitting opposite him, reading. Alec Guinness's autobiography, I think. I said I thought it was terrible. He said he had read it and agreed. I said I didn't think I'd manage to finish it. He took it from me and threw it out of the window. 'That'll save you the trouble,' he said.'

With an introduction like that, marriage was inevitable. Now, four years later, the pair live in south London in a house purchased, so the tabloid story insists, from the proceeds of Merton's television commercials for Imperial Leather soap. 'Bollocks,' claims his wife. 'If bloody only. We have a monster mortgage. Hence the fact we have to work so often.'

And often together. In the television film of An Evening With Gary Lineker, Merton switches from the title role to playing a nerd with a pickled onion habit and a dreadful wig ('actually that's his own hair,' claims his wife). And later in the summer they open in a West End production of The Live Bed Show, another Arthur Smith play based on the experiences of his friends.

'Arthur is a great big thief,' Caroline says. 'All writers are. They have no lives of their own, so they steal the lives and lines of others.'

An Evening With Gary Lineker is about a couple who, because of the husband's football obsession, cannot face up to their crumbling marriage. Is Smith mining a vein close to the Imperial Leather home here (particularly since the Merton/Quentin liaison is regularly ridiculed on Have I Got News For You)?

'It is amusing the way people seem to think that because Angus Deayton says he is having an affair with me we must be,' Caroline says. 'No, it is not true. The marriage bit was added by Arthur to add a bit more spice to the proceedings. Besides, it can't be us. Paul isn't interested in football.'

In the meantime, next Tuesday, all the protagonists of that July day in 1990 will gather at the Merton residence for a party. Will they, at this party, watch the film?

'No, because then Arthur would write a play about his friends watching themselves on television watching television,' says Caroline.

And, more importantly, will Gary Lineker be there?

'No. He's in Japan. Sadly. I became rather obsessed by him during the run in the West End. My character has an imaginary love affair with him, and one night I was delivering the line 'The thing about Gary is' when I saw him. Sitting there. His face seemed to come at me, his head was surrounded by a glowy sort of light. I dried. Just stared at him. He came three times to the show. Brought the entire England squad one night. I don't think they enjoyed it.'

Her four-year-long evening with Gary Lineker reaches its apex when, in the closing scene of the film, the two of them kiss. 'Tongues were not involved,' she says. 'Sadly, our lips met only very, very lightly. I insisted on more than one take. Several takes, actually. And I feel I am free to reveal that, since Gary is so pure his farts smell of violet, his breath is a delight.'

'An Evening with Gary Lineker' is on ITV on Tuesday, 14 June at 8.30pm.

(Photograph omitted)