It is to laugh

I used to hear people all the time say "It is to laugh". Usually in some overly dramatic humorous fashion. Where did that come from?

The origin of this, I believe, is the French phrase, "C'est à rire," which, translated literally as "It is to laugh," caught Johnny Carson's fancy. He repeated it often on his show, in a low-key manner, meaning roughly, "That's funny" (i.e., humorous), but often without great enthusiasm.
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For some reason, I can see Judy Holiday saying that.

Or perhaps Jean Hagen (Singin' in the Rain)? Google News Archive has hits back to the 1900's and even a few earlier.