He worked with Melba, tackling Ring opera (2,6)
I believe the answer is:
la boheme
'opera' is the definition.
(I've seen this before)
'he worked with melba tackling ring' is the wordplay.
'worked with' indicates anagramming the letters.
'tackling' indicates putting letters inside (I've seen this in other clues).
'ring' becomes 'o'.
'he' anagrammed with 'melba' makes 'labheme'.
'labheme' placed around 'o' is 'LA BOHEME'.
(Other definitions for la boheme that I've seen before include "musical work" , "18 [OPERA]" , "Opera by Puccini" .)