BILLY RAY CYRUS is begging his wild-child daughter MILEY to call off her upcoming wedding to Aussie hunk LIAM HEMSWORTH.

Amid reports that the “Hunger Games” hottie cheated on Miley – and fears that Liam used the former Disney star to boost his career – the “Achy Breaky Heart” crooner has launched a cam­paign to convince his daughter to dump Liam before she gets her heart broken.

“Billy Ray sees the writing on the wall,” said a source. “He’s fed up with the disrespectful way Liam treats Miley by constantly flirting with other women in front of her.

“He’s had deep reservations about Liam from the start, because when Miley hooked up with him, she was the big star and he was an unknown in America.

“Billy Ray thinks Liam hitched his wagon to Miley and used her fame to turn himself into an A-list actor. He feels so strongly about it that he told Miley he’ll boycott the wedding if she goes forward with it.”

Miley, 20, and Liam, 23, who first began dating in 2009, hit a rough patch in recent weeks after he was caught getting cozy with “Mad Men” siren January Jones at a pre-Oscars party in late February. Rumors about an impending split began to swirl in early March when Liam jetted off to his home turf in Australia before continuing on to Asia for work projects.

Meanwhile, Miley was spotted without her engagement ring but squashed breakup reports by claiming that the sparkler was get­ting repaired. Then, on March 20, Miley tweeted a photo of herself wearing the ring – and Liam was spotted back at LAX.

But even if Miley and Liam are patching things up, the same can’t be said for the tense relationship between her fiance and father.

“Billy Ray won’t stand by and watch Miley get her heart bro­ken,” added the source. “He’s praying she takes his advice before she really gets hurt.”