Keith Urban, Vince Gill, Kacey Musgraves, Carrie Underwood are just a few of the country stars teaming up Tuesday night (May 6) for the annual We're All 4 the Hall benefit concert. During Monday's rehearsals at Nashville Bridgestone Arena, CMT Hot 20 Countdown caught up with several of them to talk about the concert that raises money for the Country Music Hall of Fame and Museum.

"I always look forward to it," said Urban, who helps organize the event. "I mean, putting the guest list together and hoping that everybody we invite can come out, then figuring out the songs to do, figuring out the theme and then figuring out who might want to come based on that theme."

The museum is "an entity and a spirit that everybody wants to support," he said.

"I always say this whole thing really started with Vince suggesting that every artist donate one night's proceeds to the Hall, and from that simple, really pure idea, this entire thing was born," Urban noted.

To date, the We're All 4 the Hall series has raised over $2 million.

Gill says he is most excited about the opportunity for the singers and musicians to get back to the basics.

"For us, to get to be guitar players, for us to get to be musicians like we deep down always love being -- I mean, we stand up front and we sing the songs, write the songs and do all that," Gill said. "And it's fun, but we really get to go back to exactly who we really are.

"It's a pretty cool bunch of artists over the five years that have done this, and hats off to Keith for doing all the inviting and always having a theme and always having his head wrapped around what he envisions the night being like. I'm just the other guitar player, and it's great fun for me!"

This year's event is billed as "Songtellers (A Large Intimate Evening)." The theme will allow the stars to explain the stories behind the songs they've written or recorded. Others scheduled to appear are Brantley Gilbert, Brett Eldredge, Darius Rucker, David Nail, Deana Carter, Kip Moore, Lee Ann Womack with Buddy Miller, Mary Chapin Carpenter, Reba McEntire and Ronnie Milsap.

In their first appearances at the fundraiser, Musgraves and Underwood both admit they feel honored to be a part of the cause.

"I've never honestly gotten to come and even to sit in the audience," Musgraves revealed. "So this is a treat for me to be able to be part of it. ... I love the Hall of Fame and what they are preserving. I think it's really important for the future of country music to have that there. But it's also going to be just a really fun night and a lot of incredible legends coming together to support something awesome."

Underwood agreed that the concert is just as much fun for artists as it is for fans.

"It's a giant jam session, and I feel like so many of us stress so much about putting together our shows -- you know, what songs in what order and what video stuff in what," she said. "It's such an involved process. And sometimes it's just nice to [sing] two songs, and then I get to watch Reba. I mean, come on, who wouldn't want to do that?"

For more on this year's We're All 4 the Hall benefit concert, tune in to CMT Hot 20 Countdown this Saturday and Sunday (May 10-11) at 11 a.m. ET/PT.