X Factor judges’ surprise addition

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.”

She also thanked their “incredible surrogate mother” and said she feels “so blessed that we live in a world which makes this possible”.

Back in May reports suggested that Robbie and Ayda wanted to have a third child to “complete the family”, although it was not known at the time that they had chosen the surrogacy route.

Ayda ended her Instagram post by saying: “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”

The new arrival comes at an especially busy time for Ayda and Robbie as they will shortly be filming the Judges Houses and live stages for The X Factor.

On The X Factor tonight, Ayda ends up being carried by Robbie as the pair mock choreographer and singer Ivo Dimchev.

The Bulgarian’s act involves him being joined by dancers who contort into amusing positions. It prompts Robbie and Ayda to copy some of the moves as they sit on the panel. Robbie then gets on to the stage with his shirt open and tied at the bottom, showing his chest. With a cheeky dig at boss Simon Cowell’s signature style, Ayda jokes: “Did you borrow that from Simon?” Simon replies: “I was waiting for that!”

When Ayda gave birth to her second child Charlton, Robbie live-tweeted footage of her labour.

Wearing glittering red stilettos and with her feet in stirrups, she was seen joking and laughing her way through the birth alongside the Take That star.

She said: “I thought the idea was genius. It took my mind off everything – especially the pain.”

Ayda later admitted it had been her idea to document the birth online.

The X Factor with Robbie and Ayda continues at 8.30pm tonight on ITV.