One running the show (5)
I believe the answer is:
emcee
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">one running the show</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this in another clue)</span><br/ ><br/ >This is the entire clue.<br/ ></span>
(Other definitions for emcee that I've seen before include "A host of Americans" , "Someone presenting" , "Announcer" , "One presents" , "Master of Ceremonies (informal)" .)