duffy was born in nefyn, gwynedd, to an english father of irish ancestry, john duffy, who was born in liverpool and brought up in rock ferry, wirral; and mother, joyce, born in gwynedd, caernarfonshire, and brought up in nefyn, near pwllheli. she was partly raised in nefyn with her twin sister, kate, and older sister kelly ann, who was born in 1980. duffy's parents divorced when she was 10 and she moved to letterston, near the pembrokeshire town of fishguard, with her mother and sisters.