Gwen Stefani admits Gavin Rossdale is the inspiration behind her new track, 'Used to Love You'.

Gwen Stefani

Gwen Stefani

The 46-year-old singer, who split from the British rocker in August after 13 years of marriage, says this is the first time she's ever released a break-up song when she's "actually going through things in real time."

Asked if the single is about her estranged husband, the 'Voice' USA mentor said: "Oh my God. Put me on the spot!

"What I'll say about that is that I've never put a record out where I'm actually going through things in real time. Like, the 'Tragic Kingdom' [record] I wrote that over a three year period and then it came out and it was, like, two years on tour. It was a long, drawn out thing.

"I wrote that song, like, a couple weeks ago, and then I sat in front of a camera in a dressing room randomly not making a video, just to do some video for the screens behind me, and it went out and it's the video and it's, like, all very real."

The blonde beauty credits her fans for helping her get through the split.

She told Matt Lauer on the 'TODAY' show: "It's nice to do music and have that support from everybody. I don't know these people but for whatever [reason] I feel their love and energy coming back at me, and that's really comforting."

Gwen and Gavin, 49, have reportedly already reached a divorce settlement and have agreed to share custody of their three sons, Kingston, nine, Zuma, six, and Apollo, 19 months.