United Kingdom, Sept. 24 -- Penny Lancaster reveals Rod Stewart decided to have more children because of 9/11.

The 54-year-old model and her rock star husband, 80, have been married for 18 years and they were always "transparent from the beginning" about what they wanted from the relationship, with the Maggie May hitmaker not keen on expanding his family.

Appearing on UK TV show Loose Women, she said: "we were honest with each other, and we didn't actually bring the subject up again until about 2004.

"Out of nowhere, we were reminiscing and remembering those lives that were lost in 9/11, and thinking about all the children that could've been born from those couples that had sadly lost their lives.

"And then he turned around and said, ...