Sing to Williams before Sheeran comes back (8)
I believe the answer is:
serenade
'sing to' is the definition.
(I've seen this in another clue)
'williams before sheeran comes back' is the wordplay.
'williams before' becomes 'serena' (I can't justify this - if you can you should give a lot more credence to this answer).
'sheeran' becomes 'ed' (Ed Sheeran).
'comes back' is a reversal indicator.
'ed' back-to-front is 'de'.
'serena'+'de'='SERENADE'
Can you help me to learn more?
(Other definitions for serenade that I've seen before include "Piece sung beneath beloved's window" , "Music played by lover" , "Song often sung under a window" , "Song to a lover" , "Play music, sing for someone" .)