Actor Holbrook and others (4)
I believe the answer is:
hals
'actor holbrook and others' is the definition.
(I've seen this in another clue)
This is all the clue.
(Other definitions for hals that I've seen before include "portrait painter" , "Laughing Cavalier artist" , "Frans - , Dutch painter (The Laughing Cavalier)" , "Frans --, Dutch artist" , "Sixteenth to seventeenth century Dutch artist known for portraits" .)