Since scoring her first major country hit in 1991, Pam Tillis has been asked countless times: “When are you going to record an album of your Dad’s songs?”

Now, the dutiful daughter of Mel Tillis has an answer. It’s All Relative, her first album for Sony Nashville, is due Aug. 27. It features 13 of her father’s songs, both famous and unfamiliar, done in Pam Tillis’ own musical style.

“We just finished it last night, literally,” she tells CMT.com on Wednesday [May 29] with a mix of pride and exhaustion. “Oh my God, it’s like the project that ate New Jersey. I’m just so tickled to be done with it and so excited to get it out.”

Although Mel Tillis has not been elected to the Country Music Hall of Fame, several entertainers who are members earned hits with his compositions. Pam reprises a few on the new set: Patsy Cline’s “So Wrong,” Waylon Jennings’ “Mental Revenge,” Brenda Lee’s “Emotions” and Faron Young’s “Unmitigated Gall.”

“Detroit City,” the 1963 Bobby Bare hit, is included, but “Ruby Don’t Take Your Love to Town,” a 1967 country hit for Johnny Darrell and a 1969 pop hit by Kenny Rogers and the First Edition, is not.

“That’s such a guy song. We played around with writing a female lyric, and I thought, ‘Nah, this is sacrilegious!’” she chuckled.

She also unearthed the unknown song “Not Like It Was With You,” amazed that nobody had noticed it earlier. “It is the greatest song! I was like, ‘How did this get lost?’ It is really good. It sounds like something you’ve heard before.

“There are so many great songs! Narrowing it down was the biggest pain. It was hard –- [I was] throwing darts at a dartboard!” she giggles. “No, I just picked things that made sense for me to sing. Things that I might record anyway, even if they weren’t Dad’s. … Dad’s got a lot of songs that are definitely male-oriented that I couldn’t do, so I stuck with stuff that I could sing.

“[After hearing] some of the treatments I did … Daddy said, ‘I don’t think I would have thought of that, but I like it.’ It was cool for me to play back those songs for him in ways that are totally different. He thought that was so neat. He was like, ‘I didn’t know that song would do that.’”

Pam Tillis, 44, has long included her father’s songs “Heart Over Mind” and “I Ain’t Never” in concert –- both are on It’s All Relative -- and she often appears at his theatre in Branson, Mo. Daughter and dad also recorded a duet, which neither wrote, for Pam’s 2001 album, Thunder & Roses.

“The first several years of my career, I thought it was just too soon,” she says of her early reluctance to embrace a project devoted to her father. “I wanted to establish myself as an artist, and I didn’t want to ride on any coattails. I had a lot of my own music to get out there, but now seems like a good time. I’ve been talking about it seriously for five years now. I just changed record labels and it seemed like time to do something different.”

Tillis was among Arista Nashville’s original artists, along with Alan Jackson, Brooks & Dunn and Diamond Rio. The Top 10 hits “Don’t Tell Me What to Do” and “Maybe It Was Memphis” introduced her to a mainstream country audience. She captured the CMA female vocalist award in 1994 and won critical acclaim for the album Sweetheart’s Dance. In 1995, she produced the album All of This Love, a rare feat for a woman on Music Row. Her Greatest Hits featured the Grammy-nominated hit “All the Good Ones Are Gone.”

For It’s All Relative, Pam produced nine tracks in Nashville and invited Mel and the extended Tillis family into the studio for “Come On and Sing.” She also traveled to Austin, Texas, where Asleep at the Wheel’s Ray Benson co-produced four tracks including a traditional country take on “Burning Memories.”

“The one thing I was going for was to not let it be overly slick,” she says. “There are several types of styles on the record, some of the really traditional honky-tonk. And shuffles! On a Mel Tillis tribute, there’s going to be a shuffle.

“A great song, you can do any kind of way,” she says. “It just holds up. We did several different versions of different songs, and any way you played them, they were cool!

“Over the years, Dad was a staff writer and writing for a lot of different artists, so I think people will be surprised at the diversity. If you think, ‘There are so many styles of music on this record,’ don’t blame me! Of course, people know I like to do that. On every record, I always do different things. I like eclectic. So it was perfect. There’s everything from Texas shuffles to torch songs to some bluesy things.”

When word spread about the project, Tillis’ supporters -– of both father and daughter –- happily joined the family affair.

“I have a home studio, as so many people do now, and we did a lot of the overdubs here. Dolly came over, and Emmylou came over, and Delbert came over,” she says, with a bit of awe. “And here’s the Jordanaires at my house! They all drove white cars and parked in formation! I said, ‘You guys even park in harmony!’ Just to hear these classic sounds in your house –- it was so cool!”

Other guests include fellow Opry members Marty Stuart on mandolin, and Trisha Yearwood on harmony. (Tillis joined the Opry in 2000.) Her boyfriend Matt Spicher (son of famous fiddler Buddy Spicher) engineered the project.

“It’s a real homespun project,” she says.

“Doing an album like this is like having a baby! I’m having a little bit of postpartum today. It’s like, ‘Now what do I do?’ I guess I’ll call some people and tell them about it.”