As the actress said to the bishop

I have been searching for years to find the meaning and origin of "as the actress said to the bishop!" Any help much appreciated.

As to its origin: The Oxford Dictionary of English Idioms describes it simply as "an idiom"; evidently it has no known originator. As to its meaning: as the ODEI says, it is "used humorously to call attention to a sexual double entendre, especially an unintended one." (VSD)