Sirius as Godfather to Harry

'You know what this means?' Sirius said abruptly to Harry, as they made their slow progress along the tunnel. 'Turning Pettigrew in?'
'You're free,' said Harry.
'Yes...' said Sirius. 'But I'm also - I don't know if anyone ever told you - I'm your godfather.'
'Yeah, I knew that,' said Harry.
'Well... your parents appointed me your guardian,' said Sirius stiffly. 'If anything happened to them...'
Harry waited. did Sirius mean what he thought he meant?
'I'll understand, of course, if you want to stay with your aunt and uncle,' said Sirius. 'But... well... think about it. Once my name's cleared... if you wanted a.. a different home...'
Some sort of explosion took place in the pit of Harry's stomach.
'What - live with you?' he said, accidentally cracking his head on a bit of rock protruding from the ceiling. 'Leave the Dursleys?'
'Of course, I thought you wouldn't want to,' said Sirius quickly. 'I understand. I just thought I'd -'
'Are you mad?' said Harry, his voice easily as croaky as Sirius'. 'Of course I want to leave the Dursleys! Have you got a house? When can I move in?'
Sirius turned right around to look at him; Snape's head was scraping the ceiling but Sirius didn't seem to care.
'You want to?' he said. 'You mean it?'
'yeah, I mean it!' said Harry.
Sirius' gaunt face broke into the first true smile Harry had seen upon it. The difference it made was startling, as though a person ten years younger was shining through the starved mask; for a moment, he was recognisable as the man who had laughed at harry's parents' wedding.

THE DEMENTOR'S KISS - Pg 402