Godfather of rock (Queen) millions recalled (2,3)
I believe the answer is:
mr big
'godfather' is the definition.
(both can mean a senior criminal)
'rock queen millions recalled' is the wordplay.
'rock' becomes 'gib' (both are nicknames for Gibraltar).
'queen' becomes 'r' (r is abbreviation regina. e.g. in ER ).
'millions' becomes 'm' (abbreviation).
'recalled' is a reversal indicator.
'gib'+'r'+'m'='gibrm'
'gibrm' written backwards gives 'MR BIG'.
'of' acts as a link.
(Other definitions for mr big that I've seen before include "Important man" , "Top man" , "boss" , "chief" .)