Move the heart of Freddie Mercury, for one (3)
I believe the answer is:
god
'mercury for one' is the definition.
(mercury is a kind of god)
'move the heart of freddie' is the wordplay.
'move' becomes 'go' (to go is to move).
'the heart of' means to look at the middle letters.
The centre of 'freddie' is 'd'.
'go'+'d'='GOD'
(Other definitions for god that I've seen before include "Divinity" , "Supreme being" , "Pan perhaps" , "Superhuman being" , "Worshipped figure" .)