A certain McCartney reported to do with the stars (6)

I believe the answer is:

stella

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

'a certain mccartney' is the definition.
'Stella' can be an answer for 'mccartney' (Stella McCartney is a fashion designer). I am unsure of the 'a certain' bit.

I can't explain the remainder of the clue.

Can you help me to learn more?

(Other definitions for stella that I've seen before include "girl!" , "Swift alias for Esther" , "woman" , "lady?" , "Paul McCartney's daughter" .)

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