Elfyn was born in Bangor, Gwynedd, was brought up in Newtown, Powys,[1] and now lives in Penarth, Glamorgan with her husband, Clwb Ifor Bach Promoter and Works Manager Richard Hawkins.
[2][3] Elfyn is a fluent Welsh speaker and has appeared as a panellist on Welsh-language channel S4C's music talent show Wawffactor.
She co-hosted Radio 1's first Welsh-language programme as part of the oneclick strand in August 2005 with Aled Haydn-Jones from The Chris Moyles Show.
Elfyn co-presented the Wales programme on BBC Radio 1 with Huw Stephens as part of the station's regional output every Thursday evening.
She joined Radio 1 in 1999 during the Cool Cymru era of music and arts popularity, as part of the aforementioned new regional output, and left in 2010 after 11 years at the station.