Go on stage because you have a sudden desire to? (3,2,7)

'go on stage because you' is the definition.
I don't know anything about this answer so I can't tell whether it can be defined by this definition.

'a sudden desire to?' is the wordplay.
I cannot really understand how this works, but
'a' is found in the answer.
'desire' could be 'impulse' (impulse is a kind of desire) and 'impulse' is found in the answer.
'to?' could be 'to' and 'to' is found within the answer.
This explanation may well be incorrect...

'have' is the link.

Can you help me to learn more?