Hilchos Lashon Hara, chapter 2, section 8

Regarding the wording of the warning, it makes no difference whether he told them not to speak of the matter he spoke of, or that he warned them that the story should not become known. In any event it is forbidden to related the derogatory information to someone else, and how much more to the person the derogatory information was spoken of.
The entire leniency of “before three” only applies where there were three listeners, but if two spoke before two, one may not speak of it further.