The iconic 60s supermodel believes Catherine is synonymous with London style and has helped boost the monarchy's popularity thanks to her natural elegance and sophisticated outfits.
She enthused in an interview with Fashionista.com: ''I think [Catherine is] wonderful and I'm a great royalist. I think they're wonderful for the country and I think she's gorgeous - [her and William] seem very happy.
''I follow what she wears in the magazines just like everyone else, and she dresses beautifully. She's stylish and classy, and she always comes across as a really nice person - which I think is why she's captured everyone's heart. And now they've got a baby! Everyone loves a baby.''
Twiggy said: ''I love Cara Delevingne, I think she's great, and I still think Kate Moss is one of the best. My favorite new model is half English and half American - her name is Staz Lindes and she's absolutely gorgeous.''
The former 'America's Next Top Model' judge also thinks London's high-street is the birth place of youth culture and truly unique stye.
She explained: ''From the early days in the '60s, we had Biba, and it was the first time you could get modern clothes for teenage people - she kind of began it. To be fair, I think we've always been the leaders in youth culture, and have some of the most innovative, slightly quirky young designers and artists.
''I think because we're an island, we've created slightly eccentric people, which I think is rather wonderful.''
The novel's author saw a cut of the film and loved each of the changes the movie's director had made.