The singer and his wife Ayda, who are currently appearing on the judging panel of The X Factor U.K, surprised fans when they announced last Friday (07Sep18) that they had welcomed a baby, daughter Colette Josephine Williams, known as Coco, via surrogacy.

Robbie, 44, explained in an interview with British newspaper The Sun that adding a third child into the mix hasn't upset the family at all.

"Coco is the most chilled baby I've ever known," he told the news outlet. "It's funny. The first baby you have, 'Shh, it's sleeping,' then you hear someone coming in that closes the door and you run downstairs and you go, 'Shh! The baby!'

"Then the third one, the television's on, the kids are playing, the dogs are barking, the baby stays asleep and the world doesn't end," he exclaimed. "I wonder if the baby is so relaxed because we are relaxed."

Robbie and Ayda are already parents to five-year-old daughter Theodora, nicknamed Teddy, and son Charlton, three, and the former Take That star said they are both enjoying giving their new sibling "lots of cuddles".

"The kids are getting on really well with her, there's no jealousy," he added. "In fact there's just lots of love and cuddles and Teddy wants to feed her all the time. So that's what's going on."

The couple announced Coco's arrival with a black and white photo of the family's hands on Instagram.

"I spy with my little eye an extra little hand," wrote Ayda, explaining the couple had had "a long and difficult path to get here, which is why we have kept it on the down low."

Ayda added that Coco was born via a gestational carrier, but did not share details of exactly when the new addition was born.