Shannon Arrum Williams[citation needed] was born on 26 May 1998 in England to a Welsh father, Lees, and to a Korean mother, Kim Jung-mi.

She attended Sylvia Young Theatre School in London and—at the age of 7—she was given the role of Cosette in the musical Les Misérables.

[5] Early in her career, Shannon's original training was focused on performing as the main vocalist for an all-girl band.

She revealed this personally in a magazine interview stating, "I was preparing for a debut as the main vocalist of a girl group, but I had a lot of greed towards singing.

"[6][7] Shannon first appeared in South Korean media on SBS's Star King in 2010 and gained attention after she displayed her singing in 2011.

[9] In 2012, Shannon released a collaboration single, "Day and Night" with Areum (former member of T-ara) and Gun-ji (Gavy NJ) and was also featured in singer Yangpa's song "Together."

[11] On 29 January, her pre-debut single "Remember You" featuring Speed's Jongkook was released to commemorate the end of her three-year training for her debut.

[12] On 12 February, Shannon made an appearance on her labelmate showcase, Speed Day, which aired on SBS MTV.

[3] On 3 March 2016, Shannon released a single called "Lachrymal Gland", featuring Soheechan as part of the 2gether project.