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Sex and the City designer Pat Fields says Sarah Jessica Parker's twin girls can look forward to some amazing designer hand-me-downs. But who will get what?

"It's going to be interesting," she told reporters Tuesday at the H&M Celebrates Matthew Williamson party in NYC. "I think that she could have fierce daughters. Fierce daughters!"

On Tuesday, the couple announced they are using a surrogate to carry the twins (so filming of the upcoming SATC movie sequel shouldn't be affected).

Fields isn't surprised the pair -- parents to son James Wilkie, 6 -- are adding to their family.

"I lived with her through the conception and the birth of James," Fields said. "I could see how much she enjoys that. And, you know, you learn that in your family. She must have learned that from her mom."

Fields said she's "glad" for the couple, who walked the red carpet together at the premiere of Matthew Broderick's new film, Wonderful World, on Monday in NYC.

Are they as strong a couple now as they were when they wed in 1997?

"I don't know," Fields said, "but let's hope!"

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