Miley Cyrus Planning 'Sexy' Album Before Marrying Liam Hemsworth

Sources say Miley is working on music that is 'very adult and sexy and believable.'

Miley Cyrus is hard at work on her fourth studio album. And while she attempted to branch out into a more adult sound on 2010's Can't Be Tamed, sources say this next studio release will be "very adult and sexy" and, more importantly, "believable."

Sources tell

target="_blank">E! News that the former Disney princess, who just announced her engagement to Liam Hemsworth, is "having fun making music for the first time in her career." She's reportedly sexing things up with producers Pharrell Williams and Hit-Boy, recording music in Miami and Los Angeles. The insider continues, "We are watching a young girl turn into a young woman."

Cyrus is also taking other steps towards a more mature sound.

She's working with music manager Bruce Flohr of Red Light Management and is no longer with the manager she had when she was closely associated with Disney. The source adds that people in her camp are referring to the musical move as "Miley 2.0."

The fact that Miley is focused on her career might make her dad, Billy Ray Cyrus, happy. Sources tell

target="_blank">Radar Online that he's hoping his 19-year-old daughter won't rush to the altar. The source adds that neither Billy Ray nor Miley's mother, Tish, was surprised by the engagement. In fact, Hemsworth asked for their permission before he popped the question.

"They knew it was coming," the Radar source said. "Liam lived with Miley and her parents when they began dating in 2009. Billy Ray and Tish love him like a son. However, Billy Ray is concerned about how young they are and he hopes that they aren't in a rush to get married.

Billy Ray hopes the engagement will be very long, but he isn't opposed to the marriage at all. Billy Ray got divorced from his first wife Cindy, though, and he just doesn't want Miley to go through a similar heartbreak."

The same day the news broke, Billy Ray tweeted his congratulations to his little girl, writing, "All I ever hoped for as a Daddy was to see my kids reach their dreams. To find happiness ... peace of mind ...

and someday know ... true love."

Hemsworth asked Cyrus to marry him on May 31, after three years of dating. They met on the set of "The Last Song." So what kind of ring did he get her? Well, she's rocking a 3.5-carat diamond in a Neil Lane-designed setting that Hemsworth helped create.