Fans of number one casino game milling around (10)

I believe the answer is:

egomaniacs

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

'fans' is the definition.
The definition and answer can be both people as well as being plural nouns.
Maybe they are linked in a way I don't understand?

'number one casino game milling around' is the wordplay.
'casino game' anagrams to 'EGOMANIACS'.
However, I'm unsure how the anagram is indicated.

'of' acts as a link.

Can you help me to learn more?

I've seen this clue in The Times.

Want a hint initially instead of a full solution? Install my app