Colleen Marie D'Agostino is an American musician and singer-songwriter from Simi Valley, California. In 2005, while attending San Diego State University she formed The Material. They released their first EP entitled Tomorrow on September 1, 2007. After six years recording and touring with The Material, Colleen started an electropop side project called With Beating Hearts. The first With Beating Hearts EP was released on October 11, 2011.

In 2013, Colleen was featured on a song called "Drop the Poptart" on Canadian producer deadmau5's SoundCloud. She was also the featured vocalist on "Seeya", the second single from deadmau5's Grammy- and Juno-nominated studio album while(1<2). "Seeya" has since gone platinum in Canada, after Colleen and deadmau5 performed the song on the 2015 Juno Awards on March 15, 2015 in Hamilton, Ontario, Canada.

After the success of her collaborations with deadmau5, Colleen was signed to the producer's imprint label, mau5trap. Her debut EP on mau5trap, Collide, was released on March 15, 2015. The "Drop the Poptart" demo was expanded and released as the first single from Collide as "Stay (featuring deadmau5)."