Sierra Deaton (Born February 11, 1991, Pennsylvania) is an American singer and songwriter. She won the third and final season of The X Factor in the USA with her ex-boyfriend, Alex Kinsey, forming the pop duo Alex & Sierra. The couple broke up in 2016 and ended the duo activities in 2017.

As a soloist, Deaton only released two singles, under de pseudonym of Essy. “Don’t Hurt,” released on February 15th, 2018, was the first one, and was followed by “Know You,” released three months later, on May 4th, 2018.

Since then, Sierra has been focusing on her songwriting career. She wrote songs such as “Lover of Mine” for the Australian band 5 Seconds of Summer’s fourth studio album CALM, and “Baby Blue” and “Bloodline” for her fiance Luke Hemmings‘ solo studio album When Facing The Things We Turn From, contribuiting vocally to those tracks, as well.