Brandon Blackstock and Kelly Clarkson
09/06/2012 at 06:00 AM EDT
A little bit country, a little bit rock 'n' roll!
After performing in Chicago on Saturday night, Kelly Clarkson
and boyfriend Brandon Blackstock swung by Nellcôte for a private after-party with fellow tour mates The Fray.
Dressed in a T-shirt, jeans and cowboy boots, the Duets
mentor, who recently earned a Country Music Association award nomination
, "didn't stop dancing" with Blackstock all night, an onlooker tells PEOPLE.
"She was smiling from ear to ear and got excited when the deejay played the Jackson 5," the source adds.
Just after midnight, Clarkson and Blackstock bid the staff farewell and headed out for the evening. But The Fray kept the party going as they sipped on Red Stag cocktails and snacked on Neapolitan-style pizzas.
– Lesley Messer