The Oak Ridge Boys have been singing for George H.W. Bush since 1983.

"We first sang for him in October of 1983 on the lawn of the White House when he was vice president," the quartet's Joe Bonsall told the mourners at the funeral mass on Thursday (Dec. 6). "He said, 'Fellas, would you sing me a few songs? I'm a big fan.

"And for decades we have sung for him. And this is a real honor to be here. What a lot of people may not know is he fancied himself to be a good bass singer. He was not," he joked.

They performed "Amazing Grace" on the altar at St. Martin's Episcopal Church in Houston, the same song Bush had invited the band to sing at his inauguration ceremonies. The 41st president passed away on Nov. 30 at 94 years old.

According to the Tennessean, that White House party back in 1983 was one where the former president was making song requests. Even for the deep cuts. “We were doing soundcheck and here came this long and lanky guy with a bag over his shoulder running toward the stage from the White House,” the band's Duane Allen recalled. “He said, 'I’m a huge country music fan, and you’re my favorite group. Is there any way you can do some songs for me?’”

On Instagram, the group shared pictures from the day and wrote, "RIP, our dear friend. We will see you and Barbara in the Place He has prepared for us."

Reba was at the mass as well, having been invited to sing "The Lord's Prayer" near the end of the service.

“It was an honor and privilege to sing at President George H.W. Bush’s funeral this morning. He was a great friend and leader and I will never forget the time we shared together,” McEntire wrote on Instagram.