Phone Empire about blockbuster (11)

I believe the answer is:

oppenheimer

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'blockbuster' is the definition.
Although both the answer and definition are singular nouns, I don't understand how they can define each other.

'phone empire about' is the wordplay.
'about' indicates an anagram.
'phone'+'empire'='phoneempire'
'phoneempire' with letters rearranged gives 'OPPENHEIMER'.

Can you help me to learn more?

(Other definitions for oppenheimer that I've seen before include "Nuclear physicist" , "Atomic expert" .)

I've seen this clue in The Everyman puzzle in The Observer.

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