Britney Spears has assured her fans she's the happiest she's ever been amid ongoing concern for the singer's wellbeing.

The 38-year-old singer took to her Instagram on Monday and uploaded a video clip of herself speaking directly to the camera, in which she addressed "a lot of comments and a lot of people saying a lot of different things about me".

"I just want to let you guys know that I am fine,” assured the Toxic hitmaker, before telling her followers: “I’m the happiest I’ve ever been in my life.

“I’m sending all of you guys a lot of prayers, wishes and a lot of love,” she said at the end of the short video.

Britney also shared a new dance video that afternoon, writing: "Dancing is such a vulnerable thing!!!! Performing for thousands of people is a cool feeling... but I also find joy in dancing for myself.

"The language of dance is really beautiful... You say so much without saying a word… using your body to express the way you feel. Live and express your body any way you want."

Fans have grown concerned for the star as she battles to end her dad Jamie's role as sole conservator of her estate.

The legal arrangement has been in place since 2008, following Britney's much-publicised breakdown. Her followers launched the #FreeBritney movement last year, fearing the singer was being forced to do things against her will and aides were pretending to be her online to assure her devotees all was well.