Robbie Williams and Ayda Field never announced they were expecting, but surprised us all this morning by revealing they've welcomed their third baby via surrogate!

Ayda made the announcement in Instagram, writing: "I spy with my little eye an extra little hand 👀 .

"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.

"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.

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

Congratulations to the happy couple!

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Ayda and Robbie are already parents to Theordora, 5, and Charlton, 3.

The couple are currently impressing viewers as new judges on this year's series of The X Factor alongside Louis Tomlinson and Simon Cowell.