The 27-year-old and husband Matt welcomed their first child Freya into the world this morning. She weighed 7lbs 2oz.
A show spokesperson this afternoon said: "Samia and Matt are delighted and everyone at Coronation Street is thrilled by the latest arrival to the Corrie family."
Smith - who plays Maria Connor in the ITV soap - became the tenth Weatherfield actor to announce that they were expecting within 18 months. Others included Julia Haworth (Claire Peacock), Andrew Whyment (Kirk Sutherland), Ryan Thomas (Jason Grimshaw), Alison King (Carla Gordon), Jack P Shepherd (David Platt) and Jane Danson (Leanne Battersby).
More recently, Graeme Hawley (John Stape) and Simon Gregson (Steve McDonald) became fathers for the first and second time respectively.