article_snippet.sent: The host was attempting to warm up the studio audience ahead of The host on Monday when The host made the off-colour gag.
article_snippet.sent: The gag is thought to have been a reference to a saying by 1930s screenwriter Wilson Mizner.
article_snippet.sent: Scroll down for video .
article_snippet.sent: But a source close to his show insisted 'a source close to the show got a big laugh.'
article_snippet.sent: It was during a Monday warm up that David made the gag .