'Normally I do this sort of shot in a stocking set and push-up bra,' she said.
'Could we get you back to back with Jonathan?' the photographer asked.
'Oh, I get it,' she said, cheering up, removing her sunglasses and resting her shoulders against Ross (they levelled off about the small of his back). 'You're remembering the publicity shot of Debbie Reynolds and Tony Curtis for Pillow Talk, right?'
'Eh?' said the photographer. 'Oh, yeah. Yeah. Right.'
In her recent film career, in Hannah And Her Sisters, Sibling Rivalry and When Harry Met Sally, Carrie Fisher has cornered a market in playing sidekicks. It was no surprise, then, that she was in Britain this week to be Jonathan Ross's foil in his television show Saturday Zoo.
'The show's producer told me to be my usual witty, erudite self,' she said back at the bar of her hotel as she cradled a Coke and a pack of Marlboro. ' 'Erudite?' I thought. 'You mean airhead-like.' '
Carrie Fisher peels off coruscating one-liners with a hit rate that Groucho Marx would have been proud of. In books, in screenplays, in journalism (her interview with Madonna for Rolling Stone magazine was a masterpiece of revelatory small talk) she has proved she has no equal as a contemporary observer of the byways of Hollywood culture. She said she had just attended the American Adult Movie Awards, a sort of porno Oscars. 'My only regret was they didn't show clips, so you couldn't go up to the person who failed to win Best Blow Job and say, 'Honey, you were robbed.' '
She has had plenty of practice watching the stars. She was apprenticed into the movie circus from birth, and was at the centre of her first scandal aged two, when her father, Eddie, abandoned his family for Elizabeth Taylor, whose husband had just died in a plane crash.
'Dad was something of a social service,' she explained. 'Marrying himself off to any passing widow who needed comfort.'
Early exposure is not something she can recommend.
'My father called seconds after my baby was born last year and said, 'Can we give Hello magazine a photo of Eddie and the granddaughter?' I said 'No sorry, it was done to me, I really didn't like it. I can't do that to my kid.' '
When Carrie was 13, her mother put her on the stage, incorporating her into a night-club act. At 17, she was in Warren Beatty's film Shampoo and at 20 she had landed a part in George Lucas's Star Wars trilogy, where, as the ethereal Princess Leia, she wore a nightie and what appeared to be a Walnut Whip on each ear.
'They did that to me,' she remembered, animated eyes rolling heavenward. 'I couldn't object to the hair- style because I thought they'd made a mistake casting me in the first place. I was so insecure, I assumed it was something George thought of simply to torture me.'
During the filming of Star Wars she spent most of her time on another planet. This was not method acting, but the result of a taste for alcohol and pharmaceuticals that she had developed through her teens. She was particularly partial to a depressant called Percodan.
'I really enjoyed drugs off and on,' she said, with a rehab veteran's candour. 'Then it became more on than off. Drugs served a purpose. They managed something in me that I was too lazy to manage on my own, this thundering emotion and verbal excitement that would roar out of me. It still can: I can still take a dinner party hostage but I try not to. Then I had no coping skills and Percodan put a little fuzziness into everything, took off the corners. I was into pain reduction and mind expansion. Trouble was, it ended up with pain expansion and mind reduction.'
After she had been detoxified, and her nose given a chance to reshape itself, Ms Fisher gave a magazine interview in which she was so droll about her rehab experience that a publisher suggested she might make a novel out of it. The result was Postcards from the Edge, which became a film. (Her grandmother, who also has a taste for a blunt gag, was heard at the premiere loudly opining: 'I don't know how they made such a great movie out of such a lousy book.') This was followed by a second novel, Surrender the Pink, for which Steven Spielberg handed her a seven-figure cheque for the film rights. Completion of her third has been delayed by child-rearing. She found, she said, that writing down her experiences served the same dampening, controlling purpose as drugs. But while she could write conversation with ease, prose was more tricky.
'I need to read to be able to write. And, you know, with the baby, you can't read much.'
What did she like reading?
'Oh no,' she said, jaw tightening, eyes narrowing. 'Any way I answer this I sound stupid or pretentious. No. No. Let's not do how clever is Carrie really. It's not a bad reading list, but I'm not giving it to you. No.'
One thing a 37-year lifetime as a public figure does for a person is make them wary. It is a wariness that extends beyond revelations about her library habits. Ms Fisher is renowned in Hollywood for her friends: in the course of an hour's conversation she drops anecdotes on, among others, Madonna, George Harrison, Warren Beatty, and her former husband, Paul Simon - none is remotely salacious. The role of loyal retainer, the mate who doesn't drop you in it, seems to extend beyond her film parts.
'Yup, that's what I am,' she said. 'I have lots of famous friends. I'm good at friends. I grew up learning how to circle around these larger bodies of light. That is the apprenticeship of being the child of celebrities, you understand what they need. I know how to participate in the celebrity life, invisibly.
'Also, people seem to want to vomit their lives over me. I have a face where people come up to me in a supermarket and say, 'What do you think of this apple?' I get people's intimacies. I had a friend have a nervous breakdown in my house recently. He knew I understood about it, so he came over my place to have it.'
It must be extremely tempting to use this sort of experience as material.
'Oh, I'd use him, you bet. He's a writer, he's used me. I was in a book of his where he was impotent with me,' she said gleefully, then changed her mind. 'Oh, no, I don't mean it. Please don't use his name. Sure, I know a lot of stuff, it would make a great tell-all. But I wouldn't do anything that was a great disclosure. I've learnt. One time in an interview I said way too much about someone. The interviewer sold the story to Spy magazine. It wasn't drastically inappropriate. It just wasn't cool.'
In Postcards from the Edge, a masterpiece of defensive humour, there was no such sensitivity about her own mental state. In that area, there appears to be little she is not prepared to reveal.
'True,' she said, reaching for another Marlboro. 'No limits on emotions. But I'm secure about it. I'm very sane about what is wrong with me. I haven't had 20 years of therapy for nothing.'
Her mother had read her books and her revelations, her grandmother had read them - would Carrie Fisher pop them on her daughter's reading list?
'Oh yeah, sure. When she's old enough. I don't think she'll be ready for the vibrator scene in Postcards when she's five. But when she really hates me, at 12 or 14, I'll slap that on her table and say, 'Right, here's some real ammunition.' And I'll definitely show her Star Wars. At the time I thought I was fat and moon-faced and frightening. Now, being 10 pounds overweight, at least, I'll proudly show her a slim mom.
'But it's an odd experience for kids, seeing their parents on screen. I remember when I was about five seeing my mom in a movie and she put her face up to William Powell, her eyes were closed and her lips puckered. And he kissed her on the forehead. I was so mortified for her. It was awful.'
And, on the subject of parenthood, she broke off the conversation to take her daughter, who had picked up something germy on the flight over, to the doctor.
'After that, this weekend I'm off to Italy,' she said, slipping her feet back into her brocaded loafers. 'I might get loaded. As a person who has admitted to alcohol dependency, it is officially OK for me to get loaded on foreign soil.'