Monarch on throne starts watching (7,2)

I believe the answer is:

looking on

'watching' is the definition.
('look on' can be a synonym of 'watch')

'monarch on throne starts' is the wordplay.
'monarch' becomes 'king' (male monarch).
'throne' becomes 'loo' (both can mean a toilet).
'starts' is a charade indicator (letters next to each other).
'king'+'on'='kingon'
'kingon' after 'loo' is 'LOOKING ON'.

I've seen this clue in The Daily Express.

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