The designer was thrilled when she saw the transgender reality TV star wearing one of her garments on her new TV show 'I Am Cait' and reached out to the 65-year-old former Olympian.
She told You magazine: ''I was very moved by that, and I sent her an email to congratulate her on her courage.
''She wrote back and then I sent her my autobiography and three dresses.''
Diane, 68, is most famous for her iconic wrap dress which was first unveiled at a fashion show at Manhattan's Pierre Hotel in 1974 and she admitted she has been shocked by its success.
She said: ''I wanted women to feel sexy, slinky and feline. I never thought I was making a fashion statement, but it turned out that I made not only a fashion statement but also a sociological one.
''Not only has it paid for my children's education and my houses and my freedom, but it has had a huge influence on millions of women.''
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