Bruce's number one Hey! Baby let emotions show (4,4)
I believe the answer is:
boil over
'emotions show' is the definition.
Although both the answer and definition are verbs in their base form, I can't see how they can define each other.
'bruce's number one hey baby let' is the wordplay.
I cannot really see how this works, but
'number' could be 'love' (love is a kind of number) and 'love' is present in the answer.
'one' could be 'i' (Roman numeral) and 'i' is found in the answer.
The remaining letters 'bor' is a valid word which might be clued in a way I don't see.
This may be the basis of the clue (or it may be nonsense).
Can you help me to learn more?
(Other definitions for boil over that I've seen before include "Evil boor (anag.)" , "Hit the roof" , "Seethe uncontrollably" , "maybe get too passionate" , "Become so excited as to lose control" .)