Identity parade (6)
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">identity parade</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for line-up that I've seen before include "ID parade" , "Form a queue" , "Identity parade" .)