Cameron Diaz would want to be in the ''best shape'' of her life before having children.

The 39-year-old actress - who is renowned for her toned physique - believes carrying a child and subsequently looking after a baby on minimal sleep would be tough, so she would want to be in perfect condition.

She said: ''If I was having a child I would think that I would want to be the strongest I've ever been in my life.

''If I was squeezing a baby through my body, if I was going to be carrying it around, it I was going to then be afterwards having sleepless nights, I would just want to be in the best shape of my life.''

The 'What to Expect When You're Expecting' star - who was most recently romantically linked to rapper P. Diddy - would love to have children in the future, and is open to any means of expanding her family.

She told the Daily Express newspaper: ''I welcome it however it may come, be it through my own body, or if I adopt a child or if I have a partner who has a child.''