"I'm not saying...I'm just saying"

[Laurence Horn]

Is anyone familiar with the use (and, as a bonus, the origin) of this
expression?  It's another one of those Gen-X/Y/Z items as far as I
can tell.  There are 32 hits on google, including one person whose
web site gives this as her "favorite quote", but I imagine it started
somewhere (TV show?  movie?).  I somehow associate it with a New
York-area working class accent, but I don't know if I'm making that
up.

larry