Bewley was born and raised in Leicestershire, one of four children with brothers Charlie, James and Andrew. Her Mother is an opera singer and her older brother Charlie Bewley played the vampire Demetri, in The Twilight Saga films. She was educated at Loughborough, Convent School before attending Loughborough High School, Leicestershire, Oakham School, Rutland and graduated from the Oxford School of Drama in 2007.
Bewley is an Honorary Ambassador for the East Midlands Rainbows Children's Hospice
After spending two years working as a Children's Entertainer, Bewley was cast as a main character in the Inbetweeners Movie. In 2013 she appeared as "Metella" in the sitcom Plebs; and as "Bunny", one of the lead characters in the E4 comedy Drifters.