The couple began its romance in 2007 and married last year, before becoming parents to baby Flynn in January.
Kerr has now revealed she initially turned the actor down when he first tried to woo her, but she eventually gave in after he refused to give up on her.
She tells Australian TV program Sunday Night, "I was reluctant - not about him, but the idea of that (him being a movie star)... I think it was his persistence (that won me over). Maybe he wanted me because he thought he couldn't have me."
During the interview, Kerr also spoke about her painful natural birth, revealing she resisted the urge to take any painkillers during her labor, but her husband wasn't quite as brave.
She explains, "I had made the decision to not have any drugs, no epidural, nothing... I remember looking at Orlando and saying 'Oh honey'... And he said, 'Give me the epidural! Seriously, if you don't want it I'll take it because right now I'm dying watching you go through this pain'. I didn't realize (Flynn) was going to be such a big baby."