Jennifer Hudson sings "Happy Birthday" to fans at New York concert

(CBS) It's not an everyday occurrence when you get to be serenaded by an Oscar and Grammy winner.

But that's what happened to two lucky fans on Tuesday when Jennifer Hudson performed on the "Early Show" in New York, which will be broadcasted on Friday.

Pictures: Jennifer HudsonPictures: Jennifer Hudson on "The Early Show"

Just a week after she was hospitalizedwith food poisoning, the 29-year-old Hudson, who showed off her svelte figure in a flirty black and white frock, delighted two concertgoers with a special birthday greeting before  encouraging the rest of the audience to join in. 

Check out the video below.