Letters from admirers (3,4)
I believe the answer is:
fan mail
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">letters from admirers</span>' is the definition.<br/ ><span class="explanation-format__explanation">(letters to a celebrity from their admirers)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for fan mail that I've seen before include "Correspondence from admirers, as to a pop star" , "Letters sent to public figures from admirers" , "Admiring post" , "Letters from a supporter" , "Letters to a celebrity" .)