Fred Astaire's sister (5)
I believe the answer is:
adele
<span class="explanation-format__ClueExplanation">'<span class="explanation-format__original">fred astaire's sister</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 adele that I've seen before include "Performer" , "Popular female singer" , "girl" , "Singer with albums titled 19, 21 and 25" , "Female singer from London" .)