The 2009 Lions wing was given a second chance by the Blues after failing to secure an academy contract with the Ospreys in 2007.
He still lives firmly within Ospreys' territory on the outskirts of Swansea. But after signing a new three-year deal in the capital city, Halfpenny insists his heart lies in Cardiff.
"The Blues is where my home is, and where my heart is now. They were the ones who gave me that second chance and I'm so thankful," said Halfpenny.
"If it hadn't come my way then God knows what I would be doing now. I've just signed a new contract and I feel I belong here."
Now Halfpenny is determined to celebrate his new contract by punishing his old side as the Blues look to reignite their push for the Magners League play-offs.
"It's great to go back and play against the side from where I come from and fires me up a bit more," added Halfpenny.
"There are Ospreys boys I was in the academy with so it would be nice to go back there and win.
"There'll be a few bragging rights between us, we beat them at home this year so hopefully we can do the double! The intensity is unlike any other game in the Magners.
"The Ospreys are full of Wales boys and it's not been long since we all separated. We've been friends for the last few weeks, but I can assure you it will be different on Saturday.
"There's added spice this time because of the situation we're in. It would be a huge disappointment for us if we didn't at least contest the play-offs
"We know what we have to do, put in a performance and get this result."