You or I might regard it as a rather odd last day at the office, but all that proves is that we settled for very boring jobs. Dawn French and Jennifer Saunders are singing Abba's Dancing Queen at the tops of their voices.
Dawn has a hammock - oh no, silly me, it's a bra - over her Hawaiian shirt, and a pair of underpants on her head. Jennifer is doing some sort of cheerleading manoeuvres with a lilac feather boa.
The moment is made all the more surreal by the fact that Joanna Lumley is challenging them both in the crazy vocal stakes - and wearing white stilettoes to boot.

Mamma Mia! Here they go again: French & Saunders appear in a sketch for Comic Relief, based on the hit film

Is this menopausal madness we are witnessing? Well, no. Rather, it is the last ever French & Saunders sketch, which is being filmed for Comic Relief. And they've managed to come out with a belter to finish things off - a version of Mamma Mia! that manages to be even more cheesy than the original.
It features Jennifer 'doing' Meryl Streep, with wig, dungarees and hippy anklet. Meanwhile, Dawn takes on the role that Julie Walters made her own in the movie, but makes it a little, um, bigger.
As usual they have roped in an eclectic load of showbiz chums.
There - with all the men gazing adoringly at her - is Sienna Miller, who plays Jennifer's daughter.
Why Sienna? 'She's the most perfect person we could think of,' says Jennifer. 'She's so lovely and... shiny.'
Philip Glenister, who always does macho well, is one of the male leads. So is Alan Carr, who is neither shiny nor macho, but manages to steal the show.
Then there's Matt Lucas, who does well to escape the day's filming without being whacked round the head by his co-stars.
'Come on ladies,' he shouts at one point. 'If you move faster you can't see the wrinkles as well.'
You get the impression that Dawn and Jennifer get up to these kinds of capers in their own kitchens of a Friday night, or - and perhaps this is the point - would if life didn't get in the way.

The original: French & Saunders decided to send up Meryl Streep in Mamma Mia because everyone has seen the film

'That's true,' admits Dawn, when the music stops. 'I often say that the only reason I come to work is to get some time with Jennifer. Left to our own devices, we'd never see each other because it gets so complicated to meet up. It is an odd job, though, isn't it? It's basically dressing up and hanging around with your mates. And we've got away with it for 30 years!'
But no more. This is the last filming the pair will do as French & Saunders.
'Shall we cry now?' asks French, but with tongue firmly in cheek. If she's upset about anything, it's that the bra she is struggling out of is too big, even for her.
'Even I didn't fill it out properly,' she complains. 'That's never happened to me before.'
Why did they choose Mamma Mia! with which to bow out? It can't have anything to do with being ladies of a certain age, and Abba fans to boot, can it?
'Of course,' says Jennifer. 'Actually, the minute I saw the film I thought, "We have to do this". The thing is, it's very difficult now to pull off these sorts of parodies because there are very few films that you can guarantee everyone will have seen, in the way that everyone saw Titanic or The Piano.'
Dawn French and Jennifer Saunders have been together so long, pictured here in 1985, they are like an old married couple who finish each other's sentences

Being subversive types at heart, they didn't actually like Mamma Mia!, of course. They don't exactly say that they emerged from the cinema sticking their fingers down their throats, but that's the implication.
'Did I hate it? Um, well, it served its purpose, let's put it that way,' says Jennifer. 'Actually, I was desperate to see what Meryl would do with it, and, to be honest, I found it hard to sneer too much. By the end, I was marvelling at what a great actress she is. Ultimately, we were insanely jealous. I mean, it was a simple idea, brilliantly done.' She hisses with mock venom.
Interviewing French and Saunders in any coherent way is pretty much impossible, largely because, like some old married couple, they have developed a habit of finishing each other's sentences, or talking over each other.
Anecdotes are often unfinished too, because the pair of them dissolve into giggles.
'We're pretty much like 13-year-old girls,' says Jennifer apologetically. 'We've been banned from going to serious meetings together. You know all those ones we have to do - with TV executives, about scheduling and ideas. Well, we both hate them, and if we catch each other's eye during them, it's just bllleuuughhh!'
She blows a raspberry to illustrate.
I ask what they remember laughing most about in all their years together - is it the 'work stuff', or the private, friendship stuff?
Interestingly, Dawn says she thinks they have laughed more in their private moments, but Jennifer reminds her that, 'no, Dawn, you're wrong. Remember that time you peed your pants?'
'I did. I peed my pants,' Dawn laughs. 'We were filming the skit of The Piano on a beach and I was the child, so I was constantly down this bloomin' hole in the sand. I was laughing so much I peed my pants. They were proper Victorian ones, too, so there were lots of layers. It was a mess, with the sand too.'
Jennifer agrees. 'The funniest times have been when we've suddenly realised the ridiculousness of what we are doing and we crease up. We've been ordered off our own sets before for laughing too much.'
Most people, mercifully, share the joke, even when they are the ones being sent up.
'I think that's because we aren't actually cruel to people. We don't set out to make them look silly.'
Have they had any celebs refuse to take part? Hugh Grant, the Spice Girls and Darcey Bussell said yes. A few have been lukewarm, apparently, which means any plans are immediately ripped up.
'You can usually tell the people who aren't going to have a sense of humour from the off. The po-faced ones usually get found out pretty soon. Our rule is if there is a moment's hesitation, either from the person or their agent, then we go, "Oh, on second thoughts, no, offer withdrawn."'
The one person they've never managed to persuade is Madonna, 'who is the same age as us,' volunteers Dawn. 'We've been stalking her for most of our careers, but she's always turned us down.
'She did send a letter once saying she would love to take part but was out of the country. I mean! Do you believe that, Dawn? As if anyone would have anything better to do than work with us!'
What's interesting about their relationship is that it has changed with every chapter of their lives. There have been difficult times, obviously. When Jennifer got married, to fellow comedian Ade Edmondson, they had three daughters in quick succession.
Meanwhile, Dawn and Lenny Henry were struggling to conceive. There were miscarriages, and much heartache, before they finally adopted their daughter, Billie.
They admit that part of what makes their union special is that when they are together they can forget the responsibilities that come with being wives and mothers. 'Our job is our fun,' says Dawn, simply. 'I believe comedy is about staying a child at heart,' adds Jennifer.
'If you have grown up you can't do comedy, simple as that. What we've managed to do is just keep hold of that little bit of us that is forever 13.'
And with that they back off to the set, these perpetual teenagers, giggling as they go.
That's all folks! As they finally call it a day, French & Saunders reflect on their highs and lows of 30 years at the top | Mail Online