John Patrick Cowsill is an American musician, best known for his work as a singer and drummer with his siblings' band the Cowsills. He has been a drummer and vocalist for the Beach Boys touring band, which featured original Beach Boys member Mike Love and long-time member Bruce Johnston. Cowsill has played keyboards for the Beach Boys touring band performing Al Jardine's and the late Carl Wilson's vocal parts. He has performed and recorded with Jan and Dean and is currently a guest lead singer for The Smithereens.