A look at this year's honorees:
Al Green, 68, born to sharecroppers in Arkansas, first made his name touring the gospel circuits of the South. Now he's one of the defining voices of Memphis soul. His songs have been covered by Annie Lennox, Dave Matthews and Bruce Springsteen.
"I don't know if there's anybody who sings quite like I do," he told The Associated Press. "No, no, one person: the president. Yeah, he sings better than me."
If only he could get Obama to sing one of his songs again, as the president famously has with a few lines from "Let's Stay Together," Green said "our record sales would go up like, 'Bam.'"
The legend has sold more than 20 million albums and won 11 Grammys. His hits include "Take Me to the River," "You Ought to Be with Me" and "Here I Am (Come and Take Me)." Green's sound reflects different parts of America, he said.
"This has just been a funny voyage," he said. "I got to meet country and western people, I've got to meet gospel people, I've got to meet hillbilly people, I've got to meet just down-to-earth regular American Midwest people — and all of them have had an effect on me."
Sting, 62, is one of the few Brits to receive the honor, and that is a badge of pride for the singer.
"The music that awakened me as a child, that inspired me to become a musician, that spoke to me, was essentially American music," he told the AP. "So, to make that journey from my hometown in the Northeast of England ... and then be welcomed by America and then given this award in Washington, D.C., with the president present is an extraordinary thing."
It was his mother's record collection that first turned Sting on to music. She had albums from Elvis Presley, Rodgers and Hammerstein show tunes and rock n' roll.
Now Sting is working on a Broadway show, "The Last Ship" about the shipyard hometown of his youth. It opened in Chicago in June and will transfer to Broadway in October.
Lily Tomlin, 75, said she was astounded to learn she will receive the honors. The Detroit native originally went to college to study medicine.
"It was like a role I was playing for a couple of semesters," she said. "I've been putting on shows since I was a little girl on the back porch ... and always imitating the neighbors or imitating my mom and dad."