Dunn became a viral video star in June when he posted video of himself singing Celine Dion's "All By Myself" around the empty airport -- just to pass the time. The video eventually made its way to Dion, who invited Dunn and his family to her Las Vegas show on Friday.
"This is a once-in-a-lifetime memory I never thought would happen but will last forever," he told the Las Vegas Sun.
Dion had previously responded to Dunn's video with a video of her own, in which she called his tribute "hilarious" and touching.
Watch Dunn's original hit -- and Dion's June 12 response -- below.