Dribble excitedly over upper-class American singer (8)
I believe the answer is:
bluebird
'american singer' is the definition.
(I've seen this before)
'dribble excitedly over upper-class' is the wordplay.
'excitedly' indicates anagramming the letters (letters excited or stimulated into a new form).
'over' is an insertion indicator.
'upper-class' becomes 'u' (similar in meaning).
'dribble' anagrammed gives 'blebird'.
'blebird' going around 'u' is 'BLUEBIRD'.
(Other definitions for bluebird that I've seen before include "US flier (but never seen over the white cliffs of Dover)" , "Racing car" , "North American songbird (once seen over Dover?)" , "Famous speedboat" , "Donald Campbell's speedboat - relative of thrush" .)