Most people know better than t o mess with Dolly Parton – and then there’s her god- daughter , Miley Cyrus.

Insiders say there’s bad blood between Dolly and the controversial “Wrecking Ball” singer over the way Miley uses her connection to the country legend only when it’s convenient.

“Dolly really Took Miley under her wing and told her from the time she was a toddler to chase every dream that comes into her head,” a friend told the ENQUIRER.

Dolly was there every step of the way as Miley’s career exploded, and she made several appearances on “Hannah Montana” as the TV teen’s “Aunt Dolly.”

When plans developed for the big-screen version of the hit show, Miley told Dolly that she wouldn’t do the movie without her. But the “9 to 5” singer was left out of the project – and Miley didn’t say a word.

When a script never materialized, Dolly contacted producers to ask for a status update and was stunned to learn that Miley had never even mentioned her name.

A dejected Dolly later said in an interview: “I’m not in the movie. I wish I had been. I assumed they were going to be writing me a part.”

And the 21-year-old hasn’t done much to mend fences.

“Miley doesn’t seem to pay much attention to Dolly these days one way or another,” the friend added.

“It breaks Dolly’s heart because she used to consider Miley the daughter she never had – but Miley only plays the ‘Dolly is my godmother’ card when it benefits her