Sorry, no, it's NOT John it's actually Paul and Paul has never actually talked about that bit or falsely claimed it was him. Why would he need to? We all know the middle section of the song is Paul's baby. It wasn't just those few lines.

You are letting the nasal quality and reverb fool you. Under all that is Paul sounding exactly like he did at the beginning of "Lovely Rita". At the very end of it where he brings it to a close you can clearly tell it is Paul. People think it's John because of the nasal tone and reverb without listening to it critically. There simply is no John voice there and I know their voices (talking, singing and clowning) like I know my friends and family's voices.

I also always assumed it was John BEFORE actually hearing the isolation and Holy Cow it's really Paul doing a John imitation. John could have never pulled that off anyways.