Caylee Hammack's debut album, If It Wasn't for You, features a collaboration that's almost too good to be true: "Redhead" with country music's most famous redhead, Reba McEntire.

Hammack's manager encouraged her to dream big for her record, but the rising singer and songwriter was still shocked when the country legend said yes. Below, Hammack shares the story behind McEntire's appearance on "Redhead," a song she wrote for her cousin.

So, the album was written, and we had pretty much finished up everything. We sat down and we talked about sequencing ... how we were gonna do it and what songs were gonna be on the album. My manager started talking about, "Hey, who do you want on this album?"

Two people I automatically said: Ashley McBryde and Tenille [Townes] ... I love these women dearly, I know them personally, and I consider them to be two of my closest friends ... And then she said, "That's awesome. We can totally have them on that song. Who else?"

And I started naming some other friends in the industry: people that are, you know, on my level or just a little higher -- still kind of breaking out, I guess, in other words, and my manager said, "No, no, no -- like, big dream. What would be a big dream?"

And I looked at the sequencing, and I was like, "How badass would it be if we had Reba McEntire on "Redhead"?" The redhead of country music on the song about a redhead -- the song I wrote for my older cousin, who's a redhead. And, I just -- yeah, I just threw that out, and then, my manager was talking to her manager. They swapped that, you know, "Caylee is obsessed with Reba," and her manager said, "Well, Reba actually likes Caylee's music; she's heard some of it."

My manager passed it onto hers. He said, "The only thing I can do is let her hear it," so he let her hear it. She liked it, so her manager said, "Do you want to sing on it, maybe?" And Reba wrote back, "Tell her to tell me what lyrics she wants to me sing, and I'll do it."

And that is -- it was just such a blessing. She never had to do that, you know what I mean? Reba is such an icon that -- she'd never have to sing with a young artist, but she did. She took that chance and she took that time ... and it just really did make 16-year-old me's dreams come true.

WATCH: Caylee Hammack's Live "Family Tree" Performance Really Shows Off Her Style

Who Is Caylee Hammack? 5 Things You Need to Know