Talk about a memorable special guest! During his Friday night (May 20) show at Chastain Park Amphitheater in Atlanta, Ga., Willie Nelson was joined onstage by former president Jimmy Carter and his wife Rosalynn. The three iconic figures, along with opener Kris Kristofferson and Nelson's band, led the crowd in a rendition of "Amazing Grace."

Nelson welcomed the former president and his wife to the stage near the end of "Amazing Grace," and after brief handshakes and hugs, the two stepped up to the mic with Nelson and could be seen singing along. Atlanta's WSB-TV reports that the Carters arrived at the venue a few songs into Kristofferson's opening set, joined by some Secret Service members.

"That's about as good as it gets," Nelson said as the Carters hugged Kristofferson, shook hands with the band and headed offstage to cheers and applause from the audience. Press play on the video above to watch the moment.

Carter, 91, is a Georgia native who now lives near Atlanta, in his hometown of Plains, Ga. He and Nelson go way back, too: Carter is a longtime fan of Nelson's music and frequently invited the singer to perform at the White House. In fact, it was during Carter's presidency that the country icon famously smoked pot on the roof of the White House.

“All the good things I did as president, all the mistakes I made — you can blame half of that on Willie," Carter once said.

In addition to his tour dates, Nelson has a big show coming up on July 4: His annual Fourth of July Picnic, which will take place in Austin, Texas.

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