Robbie Williams and his wife Ayda Field have welcomed a third child via a surrogate.

The British singer and the American actress, who are currently appearing on the judging panel of The X Factor U.K., are already parents to five-year-old daughter Theodora, nicknamed Teddy, and son Charlton, three.

But on Friday morning (07Sep18), Robbie and Ayda surprised fans by announcing that they now have a third baby named Colette Josephine Williams, to be known as Coco.

"I spy with my little eye an extra little hand," wrote Ayda next to a black and white photo of her family's hands on Instagram. "So we have been keeping a very special secret! We are delighted to share with you that we have had a baby girl....welcome to the world Colette (Coco) Josephine Williams!! It has been a very long and difficult path to get here, which is why we have kept it on the down low."

Ayda went on to explain that Coco is her and Robbie's biological child and that the infant was born via a gestational carrier.

She did not share details of exactly when the new addition was born.

"Family comes in all forms, and this little lady, who is biologically ours, was carried by an incredible surrogate mother, to whom we will be eternally grateful. We are over the moon to have this beautiful baby girl in our lives and so blessed that we live in a world which makes this possible," the 39-year-old shared.

To conclude, Ayda asked that fans respect their privacy as they adjust to being a family of five.

"As with Teddy and Charlie, we ask that you respect Coco's privacy and allow us to grow into our new team of 5! #TeamWilliams," she added.

Robbie and Ayda married in 2010.