ClariS is a Japanese pop music duo and idol unit. The members are high-school girls Clara and Alice from Hokkaido. ClariS was originally known as "Alice Clara". ClariS began singing covers of songs mostly featured in anime and songs originally sung by Vocaloids. They posted their cover song in Nico Nico Douga video sharing website between October 2009 and June 2010. In September 2010, ClariS was signed to SME Records. They released their first single "Irony" in October 2010. That song was used as the opening theme to the 2010 anime "Oreimo". ClariS released six more singles between 2011 and 2013. Their debut album "Birthday" was released in April 2012.