Bighead Romeo coming in — he loves being on the job (10)

I believe the answer is:

ergomaniac

'he loves being on the job' is the definition.
(ergomaniac means someone who loves to work)

'bighead romeo coming in' is the wordplay.
'bighead' becomes 'egomaniac' (bighead can mean an egotistical person).
'romeo' becomes 'R' (phonetic alphabet: alpha, bravo, charlie etc.).
'coming in' is an insertion indicator.
'egomaniac' placed around 'r' is 'ERGOMANIAC'.

(Another definition for ergomaniac that I've seen is " One's a workaholic".)

I've seen this clue in The Guardian.

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