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.