Iman disliked ''big gowns'' because she thought they ''overwhelmed'' her ''Somali body''.

The 62-year-old model - whose real name is Zara Mohamed Abdulmajid - used to think she couldn't ''pull off'' extravagant dresses with large skirting because she felt being ''very small boned'' and having a slender frame would make the garment look ill fitting.

She told Harper's Bazaar Online: ''I've always told him [Giambattista Valli] jokingly, 'I'm not Sarah Jessica Parker.' I'm much taller than she is, but somehow she pulls off these huge gowns effortlessly. I don't like big gowns. I have a Somali body; we're very small-boned, so things can overwhelm me.''

But when Iman received the Fashion Icon Lifetime achievement honour at the CFDA Fashion Awards in 2010, she called on the 51-year-old designer to create a ''timeless'' ensemble for her to wear for the prestigious bash.

Iman - who has 17-year-old daughter Alexandria with her late spouse David Bowie and 39-year-old Zulekha with her ex-husband Spencer Haywood - said: ''I was in a car coming home from the airport in 2010 when Diane von Furstenberg called me and said, 'Darling, the CFDA has nominated you.' And I'm like, 'For what? I'm not a designer.' And she said, 'The Fashion Icon Award. It was unanimous.' And I said, 'Well, I'm honoured.' Then automatically I was like, 'What the hell am I going to wear?'

''Giambattista [Valli] had sent me a couple of dresses for other events, and beautiful as they were, they took up the entire room.

''When I was nominated I contacted Giambattista, and he sent some pictures, and I was like, 'This is the dress!' When you know, you know. So he sent the dress to me in New York, and I had a lot of fittings; we were still tweaking it at the very last minute. I wanted this dress to be like it was cut for me. You see some celebrities on the red carpet, and the dress is way too long, and you think, 'Why didn't anyone hem it?' It's one of those things someone in fashion knows. I could walk in this dress; it was easy. I wore it with a classic black satin Manolo Blahnik heel. I also wanted my hair and makeup to transcend time. That's why I chose a chic chignon. I didn't want any lip, just a little bit of a smoky eye.

''And I don't want to wear something that I'm worried about how to walk in all night.

''I knew I wanted something that would transcend time, that nobody could ever put a date on. I didn't want a colour, so if you look at a black-and-white picture it could have been 1950. It had to be couture and have a presence but feel timeless and iconic''.