When did Self-Deprecating Shatner become standard Shatner?

[Frylock]

I remember seeing the movie Free Enterprise several years ago (must have been around 1998 or so) and being quite amused, and a little surprised, by the self-deprecating way in which Shatner portrayed himself. Of course, now, that's his standard on-screen persona.

But was I right to be surprised back then? Or did this self-portrayal precede that movie?

[Odesio]

There was the famous Star Trek Convention skit where he told his fans to "get a life" because they wasted their lives on something he did "on a lark" back in the 80s.

[Markxxx]

It became the standard when Mr Shatner found out he can make a lot more money selling himself that way