Los Angeles - Britney Spears is facing embarrassment over sales of her new album.
According to early figures, Britney Jean, the singer's eighth studio album shifted just 6 400 copies on its first day of release, including pre-orders.
The record, which features her single Work Bitch, is currently at number 14 in the UK Album Chart and was released on Monday, after being streamed on iTunes for a week for fans.
Critics have described the songs as "disappointing" but the 32-year-old singer said she is proud of the effort.
In an open letter on her website, she said: "I poured my heart and soul into this album.
"I know I keep telling you it is my most personal record yet, but it's true and I'm really proud of that.
"I have been through a lot in the past few years and it has really inspired me to dig deeper and write songs that I think everyone can relate to."
Her last offering Femme Fatale, released in 2011, reached number eight in the UK Album Chart and sold 60 000 units.