Celia, 34, gave birth to a baby girl and the couple have named her Elise.
The couple married in June last year, and Elise is the first baby for journalist Celia, but number four for TV interviewer and former Mirror editor Piers, 46. He has three sons, Stanley, Bertie and Spencer with his former wife Marion. Celia is the daughter of former conservative MP George Walden.
Their daughter was born at celeb favourite Cedars Sinai Hospital in Beverly Hills, where they have been based since Piers started presenting Piers Morgan Tonight for CNN.
Congratulations Piers and Celia!