Twelve years after country queen TAMMY WYNETTE‘s death, a battle is raging over the legend’s fortune!

Her children are launching a legal war against a former Dallas Cowboys cheerleader they believe pilfered millions from the late singer’s estate – and even tried to move Tammy’s body for a tourist attraction, The ENQUIRER has learned exclusively.

"Tammy Wynette would roll over in her grave if she knew what had happened!" said California attorney Paula Canny, who represents Tammy’s six kids.

She’s filing suit on their behalf against ex-cheerleader Sheila Slaughter, a former TV producer who was a friend of Tammy.

Sheila, then 32, started dating Tammy’s 63-year-old widower George Richey just months after Tammy died in April 1998. Sheila and George tied the knot in 2001.

Richey, a musician/songwriter, died of advanced emphysema at age 74 in July of this year. Tammy’s children believe Sheila tricked an ailing Richey to grab millions that their famous mother wanted them to have.

"We believe Sheila got George and others to empty a trust fund worth at least $900,000 that Tammy had willed to her children," Canny told The ENQUIRER.

Sheila also was named the beneficiary on a $500,000 insurance policy Tammy left for her children, payable when Richey died. Canny has had the company stop payment.

But even worse, since Richey’s death, Tammy’s children have discovered they’ve lost the rights to her music catalog, her name and likeness, as well as her trademarks – "The First Lady of Country Music" and "Stand by Your Man."

"Those rights were supposed to go to Tammy’s children – and they’re worth millions!" Canny told The ENQUIRER. "George was allowed to receive an income from Tammy’s songs, but he wasn’t allowed to sell them.

"Tammy stood by her man, but he didn’t stand by her, and we believe he let his young bride manipulate him.

"No one had the right to sell Tammy’s song catalog and empty Tammy’s trusts!"