Jessica Alba is a "constant watchdog" now she is a mother.

The 'Sin City' star says she is constantly on her guard because 13-month-old daughter Honor Marie – her first child with husband Cash Warren – has become "so mobile" in recent weeks but admits she sometimes wishes she had longer to appreciate every stage of the tot's development.

She told Fit Pregnancy magazine: "Life moves so fast as a new mom. Sometimes I wish time would slow down.

"Every milestone is memorable, from the numerous wardrobe changes in her first five months due to her explosive diarrhoea to the first time she said, 'Mama.'"

When asked to give advice to other first-time parents, Jessica said to trust your instincts but still listen to advice.

She said: "What works for you may not work for others and vice versa. I have also found that it's more useful to stop and listen than to try and always have the answers."