At home in south London, Joanna Lumley is wearing a grey tracksuit and a purple cardigan. She was going to look nicer, she tells me, as she leaps down the stairs at 10.30am, but she didn't have time. Next thing we're in the basement kitchen, and she's showing me the garden, and how the straight lines of the borders have been taken out, and what she is planting. Two men are out there. Gardeners. It's as well to get this straight, as there is quite a lot of 'curtain-twitching' in her square. A neighbour rang recently to say there was a man in her garden. 'Yes,' she said, 'It's my husband. He's allowed in the garden.' Her second husband, Stephen Barlow, 38, is an opera conductor. They have been married six years. She has a 25-year-old son, Jamie, by a man she has never named.
She's amazed at the way the Jennifer Saunders generation write, perform and produce their own stuff, while her generation are only just wising up to that. Ruby Wax introduced herself backstage at the West End flop Vanilla and told Joanna she should work with French & Saunders. But she didn't meet Saunders until a read-through for AbFab at the BBC. 'I love Jennifer. But she's very disconcerting.' She pulls a long Saunders face and grunts out an 'Er - 'ello'.
Joanna Lumley is a livewire. The second daughter of a major in the 6th Gurkha Rifles, she was born in Kashmir in 1946, and those Fifties epithets - brick, sport, good egg - spring to mind. When we met she was just back from doing a corporate video in Dublin. She was spending the day cutting her new book, Forces Sweethearts, down from 43,000 words to 30,000 for the audiotape. The book coincides with the Imperial War Museum exhibition on love in wartime that opens on 12 February. At the weekend she was off to Eritrea for Comic Relief. She has a breathless way of talking, and with her diary, you can see why. She acts her stories out, running behind my chair to do a Wogan producer frantically scribbling questions for her to ask. If you were picking teams for Charades, you'd pick her first.
A pro at TV interviews, she has been both guest and host. 'The same word, in Latin. Did you know that? Fascinating.' She is very detached about her appearances. 'Part of you is a pathetic circus clown who just falls out of a box going goo-gee-goo-gee]' Don't you feel an ass? 'If you in fact are an ass, it's fine.' What if you're not? 'We most of us are in some ways.' She swanned through Clive Anderson Talks Back the other day. 'I'm fond of Clive,' she says, 'But he doesn't ask you anything. He says, 'You were in The Avengers, weren't you?' That's a closed question. The only answer is yes. On to which he can get his gag. You're in the stocks, waiting for the cabbages.'
She has quite a grand theory about the way people are sending themselves up. It's to do with the approaching millennium. 'Everybody now is doing this -' she mimes quote marks - 'all they're doing is quoting things in different ways.' At 46, she's breaking free of the quote marks that have hung around her for 25 years. The gorgeous pouting ones. It started with The Full Wax - Ruby Wax breaking into her house and finding her a drunk, dishevelled wreck. 'People who really should know better ask if it was my house.' The image-change has gone into overdrive with Patsy in AbFab.
In the new series of The Full Wax she plays 'Joanna Lumley' again. 'I was doing some filming yesterday,' she says, 'And I was playing somebody, me, who is now past it, and who is trying to get back to something that she was once successful in, ie Purdey in The Avengers.' Isn't that a bit eerie? She laughs. 'It's only silly. It's a distortion of reality which is rather nice.'
In the mountains of Eritrea she is filming a short documentary about terracing and reforestation, for Red Nose night on 12 March. Odd, isn't it, using someone absolutely glamorous? 'We're the fairy off the Christmas tree that gets stuck in the dung heap.' Why? 'Because that's a picture. If it's a duckling stuck in a dung heap nobody takes a picture. I'd love to be a nurse. I'd love to save lives. But I'm not. I have a high profile, put on big hats, wear red lipstick and get pictures in the paper. My job.'
'Absolutely Fabulous' completes its first run on BBC2 at 9pm on Thursday.