Gwen Stefani's make-up free selfie was initially only meant to be seen by Blake Shelton.

Gwen Stefani (c) Instagram/Gwen Stefani

Gwen Stefani (c) Instagram/Gwen Stefani

The No Doubt singer is usually known for her red lipstick and sleek blonde hair but stunned fans this week when she shared a picture of herself bare-faced with tousled locks.

And now the 46-year-old singer has admitted she uploaded the photo to Instagram on a whim after initially posing for the picture to send to her boyfriend.

She told People magazine: "I was just like laying there, I just got in bed and I was like, 'Maybe I'll send a picture to Blake'.

"You just start doing like fooling around with it. I had actually a new camera on my phone and I just took that picture."I probably took about 10 and that one looked cute and I was like 'I'll just post it.' "

The 'Misery' singer - who has sons Kingston, nine, Zuma, seven and Apollo, two, with ex-husband Gavin Rossdale - was deluged with compliments from her fans after posting the photo.

One wrote, "Such a beauty!!!" and another posted,"You look so pretty with no makeup.(sic)", while a third commented "U do not need a make up ! Fabulous girl ! (sic)"

Gwen recently admitted she is in love with Blake.

When asked if she is in love now, she shared: "Yeah, for sure. I don't really want to go into that relationship, and God knows what's going to happen.

"But I feel like I'm in an amazing songwriting place; instead of being closed off, I'm thinking about positivity and how I can do something creative. I'm just doing what I want to do. It's so incredible to be in that zone. I'm always looking for the next song, and now I don't have to be insecure or write about heartache."