Using 'Signed' as a Closing

When writing letters, there are closings that people usually use like "sincerely" or "best" or "thanks", etc. I have sometimes heard people (when reading letters) say "signed, John Smith". Can you use the word "signed" as a closing before a name like that?

It's used by the person reading the letter out loud in order to make it clear that the name is formatted on the letter as a signature.

And, as jsw29 states,'No, signed is not normally used in writing one's own letters in the way proposed by the OP'

It is not listed here as a common "complimentary close" . I suspect it is only used if you are reading someone else's letter out loud.