"Imagine" singer (6)
I believe the answer is:
lennon
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">imagine singer</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for lennon that I've seen before include "Assassinated Beatle" , "Famous Liverpudlian" , "See 25" , "John - (Imagine)" , "Beatle airport" .)