Ian Van Dahl is a Belgian vocal trance and Eurodance music project created by Christophe Chantzis and Erik Vanspauwen, with first singer Martine Theeuwen, who also co-wrote and sang the song Castles in the Sky. Cindy Mertens was the second singer and can be seen in the music video for Castles in the Sky; her vocal contribution was limited to live performances only. In 2001, she was replaced by Annemie Coenen, who would become front singer of the project.