In celebration of the 25th anniversary of "Achy Breaky Heart," ET's Nancy O'Dell sat down with the 55-year-old singer in Los Angeles on Monday, where he opened up about daughter Miley Cyrus' musical transition, her journey to becoming sober and gearing up to reveal her "real" self to fans.
During her tell-all with Billboard magazine that was released last week, Miley revealed she was "completely clean" and had gone three weeks without smoking marijuana at the time the interview was conducted.
"As a dad, I see Miley really just functioning on, like, a figure and a joy for life," he said. "I don't know how to break it down more than just the fact that I see a joy in her spirit and something coming from within that is just pure beauty, if you will."
"I think she just found… she's firing off all cylinders. Her thoughts, her instincts, everything is at the top of its game," he added. "Sometimes you have to clear out the junk. And then you realize what's most important. Whatever is going on, it's working for her."
It appears her sense of style has also "cleaned" up. Lately, she's been covering up her petite figure with conservative, boho-chic ensembles, a major contrast from the barely-there garb she was donning to nearly every event as the wild Miley we all came to know over the past few years.
"You know what I like about the way she looks [now?] Happy," he gushed. "You have even seen it. A month or two [ago] she sent me a picture and I said, 'You look so happy.' I'm here [as her dad], and she's beaming with happiness. That means more to me than anything. That's what I want Miley to look like -- happy."
Billy also opened up about his daughter's forthcoming album, which includes her all-new track, "Malibu," a love song dedicated to the pop star's fiancé, Liam Hemsworth.
"I'm so excited about this album. Miley really leaned into her roots with this new album, 'Malibu' in particular," he gushed, telling ET that he hears a lot of influences from The Beach Boys, Johnny Cash, Waylon Jennings and Dolly Parton.
"There's a lot of influences in Miley's roots, even to some of the sounds of Lynyrd Skynyrd," he explained. "I mean, the sounds that were roaring out of our house and the people that was coming through our house as great songwriters -- Carl Perkins and Waylon, Hank Cochran, some of the greatest songwriters in the world. Ed King, who wrote 'Sweet Home Alabama,' was frequently at the house…"
"I think Miley absorbed a lot of those sounds and a lot of that conversation," he continued. "Especially hearing Waylon say to me at the kitchen table, 'Son, what's the definition of an outlaw? One who has been outlawed, welcome to the club.' Oh, thank you, Waylon. Miley heard that and then as she pursued it, she comes down with her guitar and he shows her [how to play] 'Good Hearted Woman.' On a guitar, you absorb that stuff. It becomes part of who you are."
Billy continued on, saying that he's "anxious for people to hear it."
"If you really want to know Miley, this record is a great place to start," he shared. "I think that's the real her, I really do."
Billy also teased that fans of the famous family may get to hear a collaboration of music at some point, as he hopes to work with both Miley and his younger daughter, Noah Cyrus. The songwriter told ET that when it comes to the music industry, he's given the two similar advice over the years.
"We love playing music together and we play all of the time and it's fun," he said. "I tell them, 'You can look at my life, man,' and just say in some ways, I failed way more times than I succeeded. But Thomas Edison said the most important ingredient for success is failure -- every time you fail, you eliminate one way that won't work, therefore being one-way closer to the one way that will."
"Well, I eliminated a lot of ways that didn't work," he continued. "When you get knocked down, you got to get up … you have to get up, and when you get up, you learn how to get up and you make an adjustment. You go on your way and that's what you do."
"Life is a series of adjustments," he added. "You make some good calls and some bad ones, and in between the two, you make adjustments. It's just like parking your car and pulling into a space. You make adjustments but you keep doing the right things and take your time. Barring unforeseen catastrophe, you'll get in the space."