Our little Miley is growing up so fast! This weekend, the Hannah Montana threw her Sweet 16 extravaganza at Disneyland (despite the fact that she won't actually turn sixteen for several more weeks) and one of the most notable acts was a rendition of "Achy Breaky Heart" performed by both her father, Billy Ray Cyrus, and Miley's new underwear-modeling beau, Justin Gaston. Though some fathers might blanch at the idea of a smooth-crooning 20-year-old dating their 15-year-old daughter, Billy Ray tells Access Hollywood that he sees a lot of himself in the briefs-clad hunk:

Billy Ray Cyrus doesn't have a beef with his 15-year-old daughter Miley dating 20-year-old aspiring musician Justin Gaston. "He actually reminds me a lot of myself when I was 20-years-old and I was living and searching for the dream," Billy Ray tells Access Hollywood of the model (and former Nashville Star contestant). "He's got a great heart and soul, and a lot of determination," Billy Ray added. "I think that's the true measure of a man, is when you measure his heart."

That, or the measurement of his International Jock thong! While we can't blame Miley for wooing Gaston, we do have to question a certain level of age-appropriate behavior — after all, what 15-year-old teen queen would invite the 46-year-old Steve Carell to her birthday party? He's married, Miley — hands off!