Abstract: System, device, and method of automatic construction of digital advertisements. An Artificial Intelligence (AI) unit is configured to receive as input: digital copies of past advertisements, and data of their performance results; as well as brand guidelines and a creative brief for automatic generation of a new advertisement. The AI unit generates a set of advertisement elements, such as logo, headline, a sub-headline, call-to-action, legal content, and an image; based on analysis of the input and detection that these particular advertisement elements correspond to previous performance results that are beyond a pre-defined threshold. An automatic advertisement generation unit generates a new advertisement by digitally placing the set of advertisement elements onto a canvas. Optionally, the system automatically generates on-the-fly in real-time a user-tailored advertisement, that is based on analysis of past performance of advertisements that were shown by the same advertiser to this particular end-user.