Declan Donnelly has become a dad and says he is "head over heels" at his daughter's arrival.
Her birth comes just a few weeks before Dec heads to Australia to film the new series of I'm a Celebrity.
Instead of hosting with his regular partner Ant McPartlin, who is taking a break from TV presenting, he is teaming up with Holly Willoughby.
Astall and Donnelly, who were married in Newcastle three years ago, said they were "thrilled to announce the arrival" of Isla on Saturday morning and that mother and daughter were doing well.
The Britain's Got Talent host shared a picture on Twitter of the baby's hand wrapped around his finger.