Bryan  set off on a world tour in spring 1977. He had just sold his London  house to John Cleese, so I decided to stay with my sister Cyndy in New  York. I threw myself into work. Bryan was touring Japan and Australia  and he wrote to me saying it was too expensive to call. I  heard from a hairdresser that he was having an affair with a model in  Japan. 
One evening in New York, I found myself sitting between Mick and  Warren Beatty at a dinner party. They were both fighting for my  attention. Mick, who was still married to his wife Bianca, made me  laugh. After dinner, we went to the famous Studio 54 nightclub. Mick  and I would celebrate that date – May 21, 1977 – for the next 23 years.  Mick was gentle, charming, funny and fascinating. I loved the way he  didn’t seem to care a hoot what people thought of him. He was confident,  cool and in control.
From  that moment, Mick laid siege to me, sending me flowers and getting me  invited to dinners where he would be seated next to me. I was flattered.  I started an affair with him on the condition that it would be over at  the end of the summer when Bryan came back from his tour. I  told Mick I could only see him every other day. It was a futile attempt  to protect my heart because I was falling in love with him.
That  year my father died. I sent a telegram to Bryan begging him to call me,  but he just sent back a telegram offering his condolences. I felt hurt,  so I turned to Mick, who was supportive and consoling. While most men  aren’t very good at feelings, he had a talent for it.
Mick  and I saw each other discreetly for the rest of the summer. For my 21st  birthday in July, he gave me an exquisite pair of diamond hoop antique  earrings. When summer  ended, we said a tearful goodbye. Bryan was due back the next day. I  felt confused, but when Bryan arrived I was happy to see him. He gave me  a beautiful emerald bracelet for the birthday he had missed.
 I hoped I could forget about Mick and  make a fresh start with Bryan. We moved to Los Angeles, but I was  terrified he would find out what I had been up to. One  night Bryan and I had dinner with Prince Rupert Loewenstein, the  Rolling Stones’ financial adviser. When Bryan was out of the room,  Rupert passed me Mick’s number. I  rang him the next day. He begged to see me again, telling me how much  he missed me, so we arranged to meet while I was appearing in some  fashion shows in Paris.
I  felt horribly torn. I missed Mick – I knew what we had wasn’t over yet. I  wanted to end it with Bryan, but couldn’t bring myself to do it. I  went to Paris and as soon as I saw Mick I knew I wanted to be with him.  After the shows, we went to Morocco for a holiday. I told Bryan I had a  modelling job. Mick and I lost our suitcase at the airport, so we  bought some Moroccan gowns.
We  felt so free, driving around in a rented car, with black kohl eyeliner  around our eyes, listening to great music. We stayed in hotels with  rooms full of sweet-scented bowls of roses and lit by candles. Mick  played his guitar and sang to me by an open fire.
We  were having lunch in Agadir one day when I ran into a fashion editor I  knew. I told her we had lost our bags and she lent us some clothes from  her photoshoot. I was still  phoning Bryan and telling him I was working. Finally he said: ‘Stop  lying. I read about you and Mick in the papers.’ The fashion team must  have spilled the beans. Bryan said: ‘Just come home and we’ll talk about  it.’
 But I couldn’t – I knew he was not  the forgiving type and I was already too much in love with Mick. I felt  bad for breaking off our engagement, but it never occurred to me to  complain about the affair Bryan had had in Japan. Bryan  took me leaving him badly, refusing to give back my clothes and  possessions. I had left a book by the bed called The Mists Of Avalon,  about druids. Bryan wrote a beautiful album called Avalon, but he never  spoke to me again.
My love  was so strong I couldn’t do anything but follow Mick wherever he led me.  I knew he had a reputation as a womaniser and he was still married,  even if he hadn’t lived with Bianca for a year, but I was hopeful. We  rented an apartment in Paris beside Notre Dame. We made love four times  a day, ripping each other’s clothes off. We never got bored or  disagreed. Unlike Bryan, Mick thought my leg-wrestling was hilarious.
As Mick’s girl, I lived life in a constant spotlight. When the Stones went on tour, we were given police escorts to hotels. If we wanted to go out, we had to be sneaked through hotel kitchens into windowless vans.
 Soon after we got together, Mick and  Bianca divorced. He wasn’t nearly as rich as people thought and had to  give her most of what he had. But we were free to be together. Having  spent years living like nomads, Mick and I felt the need to settle down. We  bought homes in New York, London, Paris and Mustique, and in March  1984, our first baby, Elizabeth, was born. We both adored her. When  Elizabeth was nine months old, we took a break on an island off the  Brazilian coast and while there I became pregnant again. Mick nearly  fainted when I told him I was carrying twins.
But  three months into the pregnancy, I was told that one twin was slightly  bigger than the other. At five months, I had another scan – one baby’s  heart had stopped beating. I was confined to my bed for a while and the emotional stress of losing one of my twins was painful.
The  surviving baby, James, was born in August 1985. He was healthy and  gorgeous, but I suffered postnatal depression, probably caused by  mourning for my dead child, and not being able to talk about it because  we had kept it secret.