Britney Spears has apologised to fans for "pretending like I've been OK", while suffering under what she calls an "abusive" conservatorship.

Axar.az reports that the star told a US court on Wednesday that she wants the conservatorship - which controls her personal life and finances - to end after 13 years.

She revealed the arrangement requires her to use birth control and prevents her from marrying her boyfriend.

On Instagram, she said she had not spoken out before due to "pride".

"I'm bringing this to people's attention because I don't want people to think my life is perfect because it's definitely not at all, and if you have read anything about me in the news this week... you obviously really know now it's not," she said.

Spears apologised to fans for hiding the truth from them, adding: "I did it because of my pride and I was embarrassed to share what happened to me... but honestly who doesn't want to capture there [sic] Instagram in a fun light!"