One German artist backing Schwarzenegger? (5)
I believe the answer is:
arnie
'schwarzenegger?' is the definition.
(I've seen this before)
'one german artist backing' is the wordplay.
'one german' becomes 'ein' ('one' in German).
'artist' becomes 'RA' (Royal Academician, member of Royal Academy of Arts).
'backing' shows that the letters should be reversed in order.
'ein'+'ra'='einra'
'einra' in reverse letter order is 'ARNIE'.
(Other definitions for arnie that I've seen before include "Arnold (abbrev.)" , "Mr Schwarzenegger, familiarly" .)