After Kelsea Ballerini came back down to earth following her Tuesday night (April 16) induction as the Grand Ole Opry's youngest living member, she shared a special backstage moment, involving two of this century's most-celebrated country stars, on social media. Ballerini's rehearsals for the big night turned into a harmony-filled moment with with Carrie Underwood and Keith Urban.

In footage posted to Instagram, Ballerini preps for her big night by rehearsing Trisha Yearwood and Don Henley's 1992 single "Walkaway Joe" with Underwood and Urban. "Sometimes the most unforgettable moments are the unplanned ones. like this, backstage at the Opry with two of my heroes singing one of my all time favorite songs," writes Ballerini. "What a life."

During the show, Ballerini backed up her Opry cred by performing three of her best-known songs, "Peter Pan," "In Between" and "Miss Me More." Afterwards, Underwood -- who'd later induct Ballerini into one of country music's most hallowed clubs -- appeared onstage for a live rendition of "Walkaway Joe." By the third verse, Urban surprised the audience by joining the pair for a grand ole celebration of '90s country.

“That was one of the coolest things that’s ever happened in my life,” Ballerini tells People. “Those are the kinds of things that happen at the Grand Ole Opry.”

Ballerini made her Grand Ole Opry debut on Feb. 14, 2015, before being invited to join the organization in early March, by Little Big Town. Onstage on Tuesday night, the country star admitted that's "rarely looked up" as her career has grown, but that night is one that "made me just stop, take a minute, be grateful and look up."

“It’s so nice and comforting to know that, no matter where life takes me, and no matter if the radio stops playing me tomorrow, and whatever happens, I can always come here, and I can always play country music," Ballerini shared. "Grand Ole Opry, thanks for seeing something in me and for believing that I’ll always love you like I do, because I do, and I will.”

The Grand Ole Opry Through the Years