SARAH JESSICA PARKER has spoken about having "tried and tried and tried" to get pregnant after son James Wilkie - and her surprise at finding out she was set to have twins, rather than just one baby, via a surrogate.

"No we didn't [know]," she confessed. "We understood that it was a possibility, but we didn't spend a lot of time on the math and science of it. We were just hopeful that we would have one healthy child. It was a wonderful shock getting two; the cherry on the sundae… [but] going from one to three children is a much bigger adjustment than becoming a mother in the first place. One child in retrospect seems a cake walk compared to where I stand today."

WATCH SJP ON VOGUETV

Despite her joy at the birth of the two-year-old girls - Tabitha Hodge and Marion Loretta, known at home as Kitty and Babe - who are biologically Parker and husband Matthew Broderick's, she acknowledges that having children by surrogate isn't necessarily straightforward.

"It just wasn't meant to happen the conventional way," she told Stella magazine. "You don't know them as well as you do a child you've given birth to. But you do have an immediate love and affection for them and what is instinctual happens."

YOU SHOULD SEE: SJP's latest looks, straight off the catwalk...

YOU SHOULD SEE: Our exclusive SJP interview on VogueTV...