Pepper is a humanoid robot capable of expressing body language, perceiving, and interacting with its surrounding environment, thanks to a wide set of sensors and actuators and exposing capabilities and high-level interfaces for natural interaction with humans. In this article, we present the development of VPepper, the Pepper virtual replica, by describing experiences focused on the interaction of the digital twin with the replicas of the smart objects in a smart home. Pepper robot has been featured with arms and hands, but its motors and actuators cannot support intensive experimental sessions and training procedures to learn how safely touch objects. Here, digital twin metaphor plays a crucial role. By a virtual and reliable replica of the robot, machine learning procedures can be seamlessly moved to/from the digital twin with a significant speedup and preventing the physical robot from deterioration. As a practical application, the reported case study is inspired to ambient-assisted living in elderly assistance. The experience, as well as the entire design and development process, has revealed VPepper and the smart environment to offer interesting opportunities for the physical accuracy of the simulation and for the availability of machine learning instruments that may be converted and adopted for real settings. A final empirical evaluation, performed involving 25 volunteer caregivers, confirms the perceived value and the potential usefulness of the system.