Penelope Cruz finds breastfeeding ''addictive''.

The 'Twice Born' actress - who has children Leo, two, and Luna, six months, with husband Javier Bardem - nursed her eldest child beyond his first birthday and intends to do the same with her daughter and admits she isn't looking forward to stopping.

She said: ''I'm supposed to get extra calories because breast-feeding, you burn an extra 500 a day. I was breastfeeding my son 13 months and I plan to do the same with my daughter. [Nursing] is addictive. It's hard ... when you have to stop.''

Despite her successful acting career, the 39-year-old beauty admits having a family has always been her main focus.

She told the new edition of Allure magazine: ''I always knew I wanted a family because of the way I grew up. Family has always been the most important thing.''

Penelope says she had a very ''free'' upbringing in a very happy household.

She recalled: ''In my house every Sunday, everybody was cleaning the house. There was always music, and everybody was dancing, sometimes naked around the house. Not hippie, but very free.''

The 39-year-old star's best friend is fellow actress Salma Hayek and their nickname for one another is huevos, the Spanish word for eggs, which stems from their lazy ways before they were parents.

Penelope - who is from Madrid, Spain, while Salma is from Spanish speaking Coatzacoalcos in Mexico - explained: ''She's one of my best friends. We call each other huevos. It was because when we were working together, we didn't have children yet, so we used to sleep much more than now. So it was a way to call each other lazy. We slept in the same bed so many times and it was like she was always trying to wake me up and call me huevos.''

Salma, 47, has a five-year-old daughter, Valentina Paloma, with her French husband Francois-henri Pinault.