This article is about Phoebe's ex-singing partner. For her niece, see: Leslie Buffay
Leslie was Phoebe's ex-singing partner. They had a great time playing together (Phoebe said that it was "the most I've had in all my lives"), but Leslie abandoned Phoebe to write television jingles. Phoebe never forgave her, and when Leslie came back into her life, she refused to get back together with her.
Eventually, Phoebe realizes that she wants to be Leslie's singing partner again, but this does not last long when Leslie suggests that they sell Smelly Cat as a jingle. Phoebe rejects this idea, claiming she is not in it for the money, telling Leslie that she needs to "get out of that jingle head". Leslie goes behind Phoebe's back and plays Smelly Cat for people at her old ad agency anyway. Phoebe leaves her with an ultimatum: The jingle or her. Leslie picks the former, resulting in another falling out. This one is permanent. Smelly Cat is put on an advertisement for kitty litter, the song being sung in a high-pitched voice.
Phoebe wrote a song about the experience. The lyrics go as follows: "Jingle bitch screwed me over. Go to Hell jingle whore. Go to Hell, go to Hell, go to Hell..."