Gwen Stefani felt like her "life blew up" as her marriage to Gavin Rossdale collapsed.
The 46-year-old star announced the end of their 13-year marriage in August, but Gwen has revealed the "unexpected" split had occurred well before then.
Gwen said: "Everybody knows that my life blew up last February. I'd just been dealing with that. Unexpected. I was going along thinking that was going to be the rest of my life and it's not. I don't know what happened."
The singer, who is currently dating Blake Shelton, also revealed the dramatic split was the inspiration behind her new hit single 'Used to Love You'.
She told KIIS FM: "There was one night, the epicenter of the whole thing - that's the most I can say about that - and the next day I wrote the chorus to 'Used to Love You'.
"But I didn't know it was 'Used to Love You'. I just had written all this stuff and it had happened to be in there buried in a bunch of lyrics that I had written."
Gwen - who shares sons Kingston, nine, Zuma, seven, and Apollo, 20 months, with her ex-husband - admitted making music during this turbulent period in her life proved to be cathartic.
She said: "I just knew that I needed to write. Even the first day that I went into the studio, I didn't want to get out of bed.
"You know when you're so down that you just don't want to do anything? I went to the studio and I wrote a song. And it wasn't just writing a song to a track or something.
"It was like sitting at a piano with a guy I didn't know and an engineer that's sitting there who I didn't know, and all this stuff is going down they didn't know."