Keith Urban and Vince Gill hosted the sixth annual All for the Hall benefit concert on Tuesday night (April 12) at Nashville's Bridgestone Arena. The two country stars rounded up a bevy of fellow artists and friends to help raise funds for the Country Music Hall of Fame and Museum's music education programs, which Urban told the audience are "near and dear to my heart" as he kicked off the show.

"It takes a lot of people to pull this together every year," Urban said from stage while performing "Somewhere In My Car" and "John Cougar, John Deere, John 3:16," praising birthday boy Gill. "But the one guy who started this whole thing -- because he had this idea that every artist should at least perform one night through the year and donate those proceeds to the Hall, and from that simple single idea, we ended up with six years of All for the Hall. I will never do this event without him.

"It's the most labor of love things we get to do," Urban added. "I think it's just an excuse to play and shred guitar as well."

Gill, meanwhile, used this year's event to honor the late Merle Haggard. He sang two of Haggard's hits, "Tonight the Bottle Let Me Down" and "The Fightin' Side of Me."

"Thursday morning, I was out on the road, and I woke up to the news that my greatest hero had passed away," Gill shared. "Tonight, I want more than anything to honor the greatest inspiration I've ever had in my life, the great Merle Haggard."

Covers were prominent throughout the entire evening, in fact: Emmylou Harris took the stage next, performing Haggard's "Kern River" and a duet with Gill, "If I Needed You." Harris was followed by Maddie & Tae, who sang a rendition of Lee Ann Womack's "Never Again, Again," followed by their No. 1 debut single, "Girl in a Country Song."

"This guy's in love, and he has his heart in the right place," Gill praised Chris Janson before the up-and-comer took the stage and gave one of the most energetic performances of the night. Janson sang his single, "Buy Me a Boat," and a cover of Waylon Jennings' "I Ain't Livin' Long Like This." During both songs, he showed off his harmonica skills and kept the crowd on their feet.

After songwriters Georgia Middleman and Gary Burr, along with students from Music City's McGavock High School, performed a song they wrote together as part of the Words and Music program, Tracy Lawrence sang "You Find Out Who Your Friends Are" and a cover of Joe Cocker's "Now That the Magic Has Gone." Maren Morris -- Urban's opening act for his upcoming RipCORD World Tour -- meanwhile, covered Dolly Parton's "9 to 5" and performed her own hit single "My Church."

Sharing the stage with wife Amanda Shires, who played fiddle, Jason Isbell offered up performances of "Traveling Alone" and Jimi Hendrix's "Little Wings." To wrap up the latter, Gill and Urban joined in for a lengthy guitar solo.

Sam Hunt performed "House Party" following Isbell, but it was his version of Haggard's "The Way I Am" that really stole the audience's hearts.

"[I was struggling] with some of the things that come along with having success as a country artist, and the obligations that come with it. The other night, I was in that kind of a mood, and missing being able to go home and go fishing, or go home and go turkey hunting, or go home and see my folks back in Georgia," Hunt confessed. "I started playing some old country songs, back in the little bathroom in my house where I write. I started playing this old Merle song ..."

In an ironic twist, Hunt made arrangements to play "The Way I Am" at All for the Hall before he found out about Haggard's passing.

"It sent chills up my spine. It gave me this really eerie feeling," Hunt continued. "It was a sad day for country music, but it made me realize how grateful I am to be able to do what I'm doing. It made me realize how grateful I am for Merle Haggard, all these boys on stage behind me and all the people who have come before me in country music, who have paved this way for me."

The crowd saved its loudest applause of the night for rock icon Peter Frampton, who sang an acoustic version of Buddy Holly's "Peggy Sue" before his own "Do You Feel Like I Do," capped off by a show-stopping guitar solo. Florida Georgia Line followed Frampton, with Tyler Hubbard acknowledging that he was a bit starstruck to be sharing the stage with both Urban and Gill. The guys sang Alabama's "I'm in a Hurry (and Don't Know Why)" and then their own single "Cruise."

Luke Bryan, who recently earned his own exhibit, Luke Bryan: Dirt Road Diary, at the Country Music Hall of Fame, acknowledged the importance of supporting the museum during his time onstage.

"The first time you walk into the Hall of Fame and see your stuff in there, it's a spiritual moment, and thank you guys for supporting this night," he shared, then launching into "Strip It Down" before paying tribute to Haggard with "Big City" and capping his set with, appropriately, "I Don't Want This Night to End."

The evening concluded with all of the stars returning to the stage to sing a medley of Haggard's "Sing Me Back Home" and "Mama Tried," while a montage of the country icon flashed across the screen.

"I will keep doing this as long as Vinny wants to do it, as long as the band shows up, as long as the artists want to do it and as long as you guys want to come," Urban promised, noting that this year's concert raised more than $750,000, bringing the grand total for all six years to $3.5 million raised. "Out of all the six years we've done, this year is the biggest year we've ever had.

"[We are] especially sending our love and prayers," Urban concluded, "and really dedicating this show tonight to the great Merle Haggard."