Sisters surprise their stepdad with the best Father's Day gift ever

Father's Day is a day to celebrate all kinds of father figures, no matter the biological relationship.

That's why Twitter user Caitlyn and her sister decided to celebrate the big day by surprising their stepdad, and making his fatherhood to them officially legal. She posted this video of them gifting their dad adoption papers and, well, get your tissues ready.

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The look on this dad's face says it all. He looks as happy to be their dad as they are to have him. Even the family pup is excited by the big family news.

People on Twitter fell hard for this family, and collectively shed tears of happiness for their new, legal bond.

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This thoughtful gift definitely made us a bit misty, too. But the other question here is: does that great pup get in on the happy adoption? We must know.