L.E.J, short for Lucie, Élisa and Juliette, sometimes Elijay, is a French band composed of three young women from Saint Denis, a city in Paris' suburbs. They got famous by condensing numerous top songs from the summer of 2015 into a mashup performance. Their song mashup Summer 2015 had millions of plays on YouTube as of August 2015 and was thus a global hit in less than a month. Their music is based on classical and world music, described by MTV reviewer Joseph Lamour as "eclectic". According to Seventeen magazine, the three vocalists were best friends from childhood, and have been performing together since 2013. Reviewer Hannah Orenstein described their sound as "pared-down but strong." Juliette plays the cello and sings backups while Elisa and Lucie are the main singers.