Devotee follower caught Queen penning single (7)
I believe the answer is:
fancier
'devotee' is the definition.
(thesaurus)
'follower caught queen penning single' is the wordplay.
'follower' becomes 'fan' (fan is a kind of follower).
'caught' becomes 'c' (cricket abbreviation).
'queen' becomes 'er' (abbreviation for Elizabeth Regina).
'penning' indicates putting letters inside.
'single' becomes 'i' (one).
'c'+'er'='cer'
'cer' going around 'i' is 'cier'.
'fan'+'cier'='FANCIER'
(Other definitions for fancier that I've seen before include "This is not so simple" , "More baroque" , "one imagines" , "More highly decorated" , "connoisseur" .)