Twenty-one-year-old Jesse McCartney is falling hard for his self-professed crush Miley Cyrus, but there’s at least one person standing between the teen queen’s May/December romance with her singing knight in shining armor-Miley’s dad, Billy Ray!

The Cyrus Family patriarch has threatened to kick Jesse’s achy-breaky butt if he doesn’t back off up off his daughter.

“There’s been serious flirting between them for a while, but Billy Ray won’t let them date,” a Cyrus family mole whispers to Star. “It’s driving Miley and Jesse crazy!”

“They’re on the phone to each other all the time, and they text each other,” another pal tells Star. “They tell each other how crazy they are for each other,” says the pal. “And how frustrating it is that they’re being kept apart!”

“…Jesse also thinks the fact that he’s been known to date a lot of young girls in Hollywood has gone against him with Miley’s dad,” a friend of the “She’s No You” singer offered to the tab.

“Jesse’s told Billy Ray that he’s willing to start out by having a chaperone of his choice around. But that’s not good enough for Billy Ray.”