Pay the bill (4,2,3,3)
I believe the answer is:
pick up the tab
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">pay the bill</span>' is the definition.<br/ ><span class="explanation-format__explanation">(I've seen this before)</span><br/ ><br/ >This is all the clue.<br/ ></span>
(Other definitions for pick up the tab that I've seen before include "Pay for something" , "Pay everyone's bills" , "Pay the whole bill" , "Foot the bill" , "Assume the expense" .)