The singer took to Twitter on Wednesday (14Dec16) to reveal she had given birth to a son.

"We have another beautiful baby boy, couldn't be happier (sic)," Kimberley wrote.

The baby is the second for the star and her husband Justin Scott, who welcomed son Bobby into the world two years ago.

The couple chose not to find out the baby's sex while Kimberley was pregnant, but it was clear she was hoping for a girl.

She said, "I don't have a preference. I think it would be lovely for Bobby to have a little brother so close in age but I'd also love to have a daughter."

Walsh's former Girls Aloud bandmate Cheryl is also expecting her first child with boyfriend Liam Payne, and Kimberley recently cooed about the singer's natural skills as a mum.

"She'll be a brilliant mum," she said. "She has loads of nieces and nephews so she's used to the madness of children."