BBC News quotes the 'Mercy' singer, making her big-screen debut in the movie, as saying that she empathises with her character Sissy, who seems not to know her place in the world.
"I feel as though Sissy's character was very close to who I used to be," she said. "I'm not saying I've changed dramatically, but there are elements of her that I think I've left behind so that's also what made me feel compelled to do the film."
Duffy also explained that she was able to pinpoint connections between the aimlessness that Sissy displays with similar insecurities she experienced during her younger years.
"This little girl [is] lost in time, looking slightly out of place, I remember being that person. She resembled something that I had experienced growing up in [Welsh town] Nefyn," the musician explained.
Before accepting the film role, Duffy had been primarily known as a recording artist. Her debut LP Rockferry secured the top spot on the UK charts in 2008 and went on to become a US top five album as well.
Patagonia opens on March 4 in UK cinemas.