The 40-year-old was placed under the legal arrangement in 2008, after suffering mental health issues and substance abuse.

It allowed her father, Jamie Spears, to take control of the pop star's movements, finances, and health care.

The conservatorship was terminated in November, giving the singer full control of her estimated $60m (£45m) estate.

On Instagram, Spears praised her lawyer, Mathew Rosengart, who she hired in July when the judge gave permission for her to choose her own legal representative.

"This man has turned my life around," she said.

And after teasing a new song just before Christmas, she added: "So many exciting projects ahead!!!!"

Spears continued: "We accidentally matched for lunch!!!!

"Thank you for being so kind and respectful to me always!!!!!!

"Pssss Mathew Rosengart … I simply adore you !!!!"

Mr Rosengart's appointment was seen as a turning point in her legal battle, with her father eventually calling for the conservatorship to be immediately terminated.

Last year, Spears listed the freedoms she was enjoying since the arrangement ended in an Instagram post.

These included "being able to have the keys to my car", "owning an ATM card", and "being able to buy candles".

Her public battle raised questions about how conservators are appointed and assessed in the US.

Original Star Trek star Nichelle Nichols and German-born artist Peter Max are two of an estimated 1.3 million people living under the legal arrangements.

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