The 32-year-old gave birth last month, and 31-year-old Cheryl wasted no time in getting involved with him.
KIMBERLEY WALSH ON BABY SON BOBBY: 'CHERYL CRIED WHEN SHE SAW HIM'
Speaking to a British magazine, Kimberley said: "Cheryl came over and helped me out when Bobby was having a windy, whingey day.
"She had a really good winding technique – I actually hadn't tried it but it's a good one. It worked and calmed Bobby and she got a massive burp straight away."
But Kimberley isn't surprised that the X Factor judge is so good with babies, as she comes from a big family.
NADINE COYLE 'DOESN'T MISS GIRLS ALOUD BAND MATES'
Kimberley continued: "She's a natural, but she'd had lots of practice as she has 12 nieces and nephews.
"It's nice to have an extra pair of hands, especially when Bobby isn't very settled."
The Girls Aloud star previously admitted to finding breast feeding Bobby hard, saying: "I've always thought breast-feeding would be the easiest thing in thew world and it's only when you speak to other people who tell you they found it painful and hard that you realise it's not just you."
Meanwhile pregnant former Pussycat Doll Kimberley Wyatt has revealed Kimberley Walsh has been giving her tips on motherhood.
She told the Mail: "Kimberley [Walsh] said that it's tough but you van do it as long as you're up for it.
"She's done a brilliant job of balancing getting back into work with being a mum and it was nice for us to be able to connect on that level."