Nicole Kidman believes Australian "fertility waters" may have contributed to her unexpected pregnancy.
According to The Australian Women's Weekly it was during production of her new film 'Australia' that she fell pregnant with her daughter, Sunday Rose.
Kidman said: "I never thought that I would get pregnant and give birth to a child but it happened on this movie."
She added: "Seven babies were conceived out of this film and only one was a boy.
"There is something up there in the Kununurra water because we all went swimming in the waterfalls, so we can call it the fertility waters now."
Speaking about the pregnancy and birth on 7 July, Kidman said: "I'm so lucky I'm so tall, so I carried small and also, I have to say, I had a birth that I was blessed with, a labour that was very good and a baby that was very good to me in that regard".
"They say that (an easy labour) is generic, so I'm grateful for that because it was beautiful and Keith was my rock through it all.
Kidman and former husband Tom Cruise adopted two children, Bella and Connor, while Sunday Rose is Kidman's daughter with her country musician husband, Keith Urban.
Talking about her three children, the Oscar winner said: "To be given this again is a beautiful thing. To have raised Bella and Connor since I was 25 and now to be able to do it again at 41...wow!"
'Australia', directed by Baz Luhrmann, is due for release on 26 December.
