Megan Fox wants to have children when her bank balance is right.

The 'Transformers' actress - who married actor Brian Austin Green - admits she is keen to start a family soon but only wants to do so when she thinks she has plenty of money to support them.

She said: "I want to have children. I've always wanted kids. I have a number in my mind of what amount of money I want in the bank so that I can protect that child's future."

The 25-year-old star adds she does not always think of herself as beautiful - despite being named Sexiest Woman in the World by FHM magazine in 2008 - because she was not the most attractive girl in school.

She said: "I was never the beautiful girl in my school - I mean, I had braces and I died my hair orange. I was not the popular girl. I was always the loner. I was drawn to this industry for other reasons."

However, she admits her job in Hollywood has not always been easy.

She added to The Hollywood Reporter: "Careers sort of go up and down. Not everybody makes a hit every single time. There's no particular technique. Most of the time it's just about survival."