Movie Scene: "It Had to Be You"

Toward the end of the film, Lynda sits alone in a cinema watching a movie. We hear some lines of dialogue delivered by a female ("It's getting kind of close to the New Year, and I'm feelin' sentimental. I'm going to sing a song that means a lot to me and...somebody else. And if you don't like it, that's just too bad. After all, I own the joint!"). She then goes right into the chorus of "It Had to Be You." Lynda watches the scene, teary-eyed.

No mention is made of which film Lynda is watching. The closing credits of "Wish You Were Here" acknowledge the song and the songwriters, but not the singer or the film it's from. I found this to be rather odd. I've Googled the dialogue, and it comes up with nothing. Therefore, I have to assume that the entire movie "scene" was assembled by the "Wish You Were Here" filmmakers. But man, it is REALLY authentic sounding—if it's fake, they did a truly outstanding job. I still wonder if this sequence is from an actual film, though.

Anybody want to weigh in on this one?