Sarah Jessica Parker didn't tell her son she was having twins via a surrogate so he wouldn't have the "burden" of keeping a secret.
The 'Sex and the City' actress and husband Matthew Broderick welcomed daughters Marion and Tabitha last June but had to keep the news of the pregnancy a secret for long time, which included not saying anything to seven-year-old James Wilkie.
She said: "We couldn't talk about the fact that we were having children with anybody outside of us for ages. I had to be very careful about telling James so that he wasn't burdened with a secret - and, more importantly, I wanted him to be able to have time to adjust to sharing his mama and papa."
Sarah and Matthew used a surrogate mother as they struggled to conceive naturally again and the 45-year-old star admits she it was hard missing out on carrying the babies herself.
She told Style magazine: "I would give birth as often as I could; I loved all the aspects of my pregnancy with our son, the good and the bad."
She has previously spoken of how time "stood still" when she met her daughters for the first time.
She said: "Meeting your children, rather than giving birth to them, felt kind of like suspended animation. The day I met them, I just remember their little faces, and my husband's face and my son's. It felt like time had stood still."