Co-cantante de 4men

Kim Won-joo (4men) & Ben 'The Serenade Part.1' (Single, 2013.10.24) 4men & Park Jung-eun 'Podemos amarnos de nuevo' (Single, 2006.01.10 ) 'Melody' (Single '2010 YWHO Winter Serenade' (Single,2010.12.17) '2010 YWHO Winter Serenade' (EP,2010.12.22)