Celebrity, on top of table, is to begin (5)
I believe the answer is:
start
'begin' is the definition.
('start' can be a synonym of 'begin')
'celebrity on top of table' is the wordplay.
'celebrity' becomes 'star' (I've seen this before**).
'on top of' indicates taking the first letters (I've seen 'on top' mean this).
The first letter of 'table' is 't'.
'star'+'t'='START'
'is to' is the link.
(Other definitions for start that I've seen before include "get under way" , "lead" , "Begin - opening move" , "Origin" , "Initiate" .)