Aguilera sang about what the customers were wearing and doing while waiting for a donut in the segment which aired on Wednesday.
She performed the songs, which could be heard from the store's loudspeakers, in the style of her hits "Genie in a Bottle," "Fighter" and "Lady Marmalade."
Aguilera, after performing her impromptu songs, would emerge from the back to greet the customers and deliver them a free donut.
"Here's a guy in all denim/ And he also has a wallet chain/ He just wants to eat some donuts/ In his Canadian tuxedo/ He is totally freaking out and he's looking really cute/ Just because he's in a song now/ And the songs about you," Aguilera sang about a customer who danced along to the performance.
Aguilera made headlines recently when she announced that she will be starting a Las Vegas residency in May at the Zappos Theater at Planet Hollywood.