The very boy
That's the one. Said when somebody finally names the person or thing you were trying to think of.
Who was it fixed the roof? Big Paddy? The very boy.

Shall I translate it into posh English for you, mucker?
Hello, dear heart. Here it is in posh English.
Who repaired the roof? Was it Patrick? Precisely the man.
Questions
What does the very boy mean in Ireland?
That's the one. Said when somebody finally names the person or thing you were trying to think of.
How do you use the very boy in a sentence?
“Who was it fixed the roof? Big Paddy? The very boy.”
Updated
On the list: Irish slang phrases