Jolie: 'Being a mother has enriched my world'

American actress Angelina Jolie, left, and her adopted son Pax Thien leave a Vietnamese restaurant in Ho Chi Minh City, Vietnam, after lunch on Friday, Nov. 11, 2011. (AP / Na Son Nguyen)

Angelina Jolie says her children are the key to her happiness.

The 37-year-old actress -- who raises Maddox, 10, Pax, eight, Zahara, seven, Shiloh, six, and three-year-old twins Knox and Vivienne with fiancé Brad Pitt -- had no idea how "enriched" a family would make her life, although the bond she had with her own mother, the late Marcheline Bertrand, gave her an idea of the strong bond between parent and child.

She said: "For me, being a mother has enriched my world so much more than I could ever have imagined.

"It's hard to say that I needed to be able to care for children to become happy in my life, but I think there's a lot of truth to that.

"My mother was very devoted to my brother and me. Having experienced that level of love makes you understand how much your children will appreciate you."

Angelina also believes the key to being a good parent is to always put your children first.

She added to OK! magazine: "I think being a good mother involves a decision to be selfless -- often there's no choice. You put your children first and then everything follows from that."