The soul legend performed his first ever duet with son-in-law Joel Madden, an experience which he says brought a tear to his eye and even prompted some kind words from the family's toughest critic, daughter Nicole Richie.
"I would love for Nicole to be just slightly gentle," says Lionel, although he was pleased to report that Nicole, who was watching backstage with her kids, gave her dad and hubby "great marks" for their performance.
Lionel tells us that Joel and Nicole's kids Harlow, four, and Sparrow, two, had no idea he was famous and had never seen him perform before Sunday night. "What's Pap Pap doing on stage with Dad Dad?" they asked.
Watch the full interview above, and hear Lionel's response to rumours that the Richies and Maddens are moving Down Under.
Lionel's country duets album Tuskegee is out now. The chart-topping album features collaborations with country music greats including Shania Twain, Willie Nelson and Tim McGraw singing their own interpretations of Lionel's hit songs.