The actor – who has two sons, Charles, seven, and five-year-old Tennyson with spouse Danielle Spencer – wanted to start a family straight away whereas the singer-and-actress was happy to delay having kids but fell pregnant when they were on their honeymoon in April 2003.
She said: "Once Russell has an idea in his head, that’s it. He was certain he wanted children, but I could have kept procrastinating about it. Then I fell pregnant on our honeymoon and the decision was made for me."
Danielle also revealed she was friends with Russell for two years before they got involved romantically as she was already dating someone else.
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She told Australia's Daily Telegraph newspaper: "When I met Russell, I was in another relationship. We were friends for two years before we got together. Then he went overseas. We had a strong connection, but it was on and off for a while.
"I wasn’t in a rush to settle down. We stayed friends and it was amazing to watch him progress in his career. Breaking America is hard work and he deserved his success when it came. I was very happy for him.
"Just after my first album, 'White Monkey', came out, he invited me to go on tour in the US with his band. We were both single and spending a lot of time together. Timing wise, things just aligned."