The 39 year-old told British Metro newspaper: "When I came in with [son] Ethan she was just like: 'Oh my God!' She just cooed over him and he gave her such a big smile."
Minogue added: "She's been asking me about that, saying: 'How's it all fitting in?' And I say: 'You can't plan any of that, you just have to go for it.'"
The star even defended the 27 year-old's mimed performance of her new single on last week's X Factor.
She added: "I thought Cheryl's performance was one of the best I've ever seen on X Factor."