In the midst of 25th-anniversary celebrations for her milestone album “I Am Shelby Lynne,” one of Alabama’s most gifted singers and songwriters has released her first new pop tune in a while.

“But I Ain’t” isn’t just a new song: It is the public’s first taste of what might come from Lynne’s return to Nashville and a partnership with Karen Fairchild of Little Big Town. Lynne has a deal with Monument Records, which announced back in March that Fairchild would work as her manager and collaborator. Singer-songwriter Ashley Monroe also is involved as a collaborator.

According to Monument, “But I Ain’t” was produced by Fairchild, Monroe and Gena Johnson. The label describes it as “a bridge between her past and future work” that samples the song “Dreamsome” from “I Am Shelby Lynne.”

Fans definitely will hear some familiar Shelby Lynne cues in the new song, such as her layered harmonies and her affinity for R&B. There’s also an interesting beat that makes you ponder what would happen if Lynne decided to explore some Amy Winehouse territory.

In her “Dirt & Fiction” blog, Lynne posted Friday that she wrote the song with Monroe, Meg Mcree and Ben Chapman. “I wanted to cut it because it felt so bitterly painful, honest and like picking at a deep scab. I couldn’t help it,” she wrote. “Add some pain to keep from feeling the current pain to take your mind off some other pain, trying to keep from crying.

“I had strength in myself I didn’t recognize that accompanied the soreness at my core but it all came from the power and blessing of music,” she continued. “Pouring everything I could hardly stand to feel into these songs, comforted by friends who saw me at my worst, lifting me up, sharing words and songs with me.”

Monument reissued “I Am Shelby Lynne” on April 5. Lynne, who grew up in southwest Alabama and attended high school in the Mobile area, had released a series of country albums prior to the 1999 project. Her dissatisfaction with Nashville led her to make a major shift to California and to soul-drenched pop, and the resulting album won her a Grammy for “Best New Artist” in 2000.

It also generated a Top 20 hit in the AAA radio format with the sunny “Gotta Get Back.” But fans in the Mobile area may remember it most fondly for “Where I’m From,” one of the most beautiful odes to life in Lower Alabama ever recorded.