As a child, Fearn showed interest in a performing career, learning how to play the piano as well as singing for elderly residents at care homes. Later accepted at Mountview Theatre School in London, she eventually made her West End debut as understudy Laura Fairlie in The Woman in White at the Palace Theatre in 2004.
Fearn has also performed in Les Miserables at the Queen’s Theatre (now Sondheim Theatre), playing a factory girl. While in the production, she was the understudy for Cosette and Fantine. She’s also starred in London productions of Annie Get Your Gun at the Young Vic, Into the Woods at Regent’s Park Open Air Theatre and Shrek the Musical at Theatre Royal Drury Lane.
In 2017, Fearn made her Wicked debut as Elphaba at the Apollo Victoria Theatre, opposite Sophie Evans as Glinda. She continued in the role for two years, with a final performance in July 2019.
Fearn has most recently played Beverley Bass in Come From Away at the Phoenix Theatre. She took over the role from fellow Wicked alum Rachel Tucker. Following Come From Away, she leads the world premiere of Then, Now & Next at Southwark Playhouse Borough.