This paper presents a model-driven approach for the design and development of digital twins. Our work leverages statecharts for behaviour modelling and for synthesizing application code to be deployed on both the physical twin (PT) and digital twin (DT). This ensures consistency between physical and digital entities and enables real-time synchronization and coordinated control. A real-time cloud database integrated with the models facilitates bidirectional communication, while user interfaces, such as a dashboard and mobile app, support monitoring, analysis and control. We demonstrate our approach with a smart home application consisting of a smart hub of lights, a garage door controller, and a fire alarm system, all coordinated through a central smart home hub. The smart home DT supports simulation, reasoning, and run-time adaptation.