The “Stern des Südens” project was developed by SIEMENS AG and multimedia artist M. Pendry and its purpose was the creation of the biggest illuminated Christmas Star. 1000 LED units (9000 LEDs in total) were installed on an Enercon wind turbine located next to the city of Munich, Germany and spectacular visual effects were created with the computer controlled LEDs. Smart Blade contributed the aerodynamic expertise in order to investigate the aerodynamic and aeroelastic performance of the wind turbine with the added LEDs and cables. Wind tunnel investigations were performed by the researchers of Smart Blade at the wind tunnel of Hermann Föttinger Institute of TU Berlin. From the wind tunnel tests we were able to estimate the energy deficit of the wind turbine due to the addition of the LEDs as well as the interference between the LED units. The optimal LED and cable configurations were identified and were further investigated with Computational Fluid Dynamics (CFD) simulations. From the experimental and numerical investigations it was possible to accurately calculate the aerodynamic loads on the LED units and the cables in order to properly size the mounting system of the LED units on the blades. The detailed analysis of the influencing aerodynamic factors and the extraction of concrete technical specifications and recommendations significantly contributed in the successful certification of the installation from TÜV SUD and of course the successful operation of the largest illuminated Christmas Star in the World.