Hey, THAT'S the girl! is a song featured in My Long Lost Sister.
[Puffycake]
Dear, Fluttershy, THAT'S the girl and YOU'RE the girl! Yes, indeed my name is Puffycake and I puff out cake aLOT! Am I such a loser? No, no I'm NOT! I must tell you...are you quite alright, are ya quite alright?
[Fluttershy]
(Spoken) Yes.
[Puffycake]
(Spoken) NOW, LET'S GO! (Singing) THAT'S THE GIRL, AND YOU'RE THE GIRL!