One of our foundational rules on notability is that claims made by celebrities are automatically, ipso facto considered notable by the very fact that they were made by celebrities. Most of the examples of this rule in application have been for public claims by celebrities. For example, a famous rock star adds a Tweet containing a claim that the average rainfall in Spain is actually less than that of Arizona and someone bounces onto Skeptics SE and asks if that is really true.
Does this rule of notability apply in cases where a celebrity has privately made a claim to the question asker? For example, suppose I bump into Vladimir Putin in a pub and he whispers to me that his country's space program has discovered liquid water on Venus. Is this a notable claim because it was made by a celebrity or does it remain non-notable until Putin repeats this claim publicly (e.g. via a speech, a Tweet, etc.)?
While the example I gave above is perhaps a little farfetched, there are plenty of people (and, I'm sure a few who post here) who actually have personal relationships with celebrities who could be in the position of hearing one of them make a dubious claim.
For another example, consider the following hypothetical question:
My mom told me that sheep have internal compasses and always face north when hungry. Is this true? P.S. my mom is Britney Spears.
Would that be on-topic?
To be clear, I do recognize that proving the existence of a private communication may be difficult and could lead to some people downvoting the question for lack of evidence. I also recognize that some users may downvote such questions out of disinterest or a feel that such questions are inherently low quality. I'm not asking about those scenarios at all, but whether such claims are on-topic at all.