Beloved tailor, fantastic member of one’s family (5,8)

I believe the answer is:

blood relative

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

'member of one's family' is the definition.
'blood relative' can be an answer for 'family' (thesaurus). I am unsure of the 'member of one's' bit.

'beloved tailor fantastic' is the wordplay.
'fantastic' is an anagram indicator (a fantastic or improbable ordering of the letters).
'beloved'+'tailor'='belovedtailor'
'belovedtailor' with letters rearranged gives 'BLOOD RELATIVE'.

Can you help me to learn more?

(Another definition for blood relative that I've seen is " in-law".)

I've seen this clue in The Times.

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