Gwen Stefani first came up the idea for this festive symphonic ballad during a run on boyfriend Blake Shelton's Oklahoma ranch. However the pop star was worried that the melody and lyrics came so effortlessly while she was jogging, she was worried that she had unknowingly stolen them from a song she'd heard at church. Speaking during an interview on The Tonight Show Starring Jimmy Fallon, Stefani explained:
"I was running and I thought, 'Ooh maybe I'll try singing something, maybe something will come," she explained, "and the whole chorus to this song 'Christmas Eve' came, it was like a prayer. I was like, 'Oh my gosh, I have to run back!'"
She added: "I'm like, 'Did I steal this? Is this from church because I feel like I know this song?' I was convinced that I stole it. I went back and I ended up finishing it."
However, when Stefani shared the lyrics with her parents, they assured her that the song was completely new and was not from a tune she'd heard during a church service, so she felt able to record it for her Christmas album.