Michael Jackson's former publicist filed a US$44 million lawsuit on Wednesday against the self-styled "King of Pop" for failing to pay her for her services.

Raymone Bain, who represented Jackson during his 2005 trial and acquittal on child sex abuse charges and later managed his business company, filed a breach of contract civil lawsuit against the singer in Washington, D.C.

She said in a statement that she had decided "with deep regret" to sue Jackson, describing him as someone "whom I have greatly admired and respected."

But she added; "Unfortunately, Mr. Jackson has elected not to honor the financial obligations of our contractual relationship, despite my numerous attempts to amicably resolve this matter. I am sincerely disappointed in Mr. Jackson's failure to honor his obligations."

US pop star Michael Jackson gestures during a news conference at the O2 Arena in London in this file photo from March 5, 2009.

Bain, who trained as a lawyer, saw Jackson through some of the most difficult moments in his career. She became his public voice for much of the lengthy child molestation trial in California, Jackson's subsequent stays in Bahrain and Ireland and the financial difficulties that resulted in the sale of his Neverland Valley ranch in California last year.

In 2006 she was appointed general manager of the Michael Jackson Company, which handles his business affairs.

She said in the lawsuit that she was hired as a spokeswoman in 2003 and that from 2006, she ran every aspect of Jackson's life including arranging housing, emergency refinancing, travel and security and scheduling meetings with record producers as the singer struggled to reestablish his music career.

Bain joins a long line of former advisers, accountants and friends who have sued Jackson in recent years over broken contracts and unpaid bills. Most of the lawsuits have been settled out of court.