A minor luminary in Hollywood (5,4)

I believe the answer is:

child star

I'm a little stuck... Click here to teach me more about this clue!

'hollywood' is the definition.
I don't know anything about this answer so I cannot judge whether it can be defined by this definition.

'a minor luminary' is the wordplay.
'a minor' becomes 'child' ('child' can be a synonym of 'minor').
'luminary' becomes 'star' (I've seen this in another clue).
'child'+'star'='CHILD STAR'

'in' acts as a link.

Can you help me to learn more?

I've seen this clue in the Evening Standard.

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