Harry stood back in shock. And then he did something amazing. He laughed. Out loud, just laughed in his Dad's face. Wait a second, not his Dad. Maybe someone else's Dad. But not his. His Dad, James Potter, died. He was dead. Deceased. Past tense. This could not be his father.
Dumbledore gave Harry sort of a Look. "Harry, I'm serious. This is you father. James T. Potter." Harry looked confused now. "But how?" Dumbledore laughed at a seemingly silly question. And the man in the corner---no! And James Potter, Dad, laughed too. "I was not killed when Voldermort came, only played dead for your protection. After I saw you defeat him, I knew you would be safe. Someone would take care of you. So I decided not to stay with you, but it was only for your safety. I knew that if Voldermort ever regained his power he would come after your powers, and then after mine if I was with you. I knew he would be angry that I had a son who defeated him. So I wanted to keep you safe, and myself also. I had some work done. Some spells I knew that could change your apperance. But don't tell anyone about those, do you realize that they discovered that in the Muggle world, something called plastic surgery and now no one looks the same way they were actually born like. Can you imagine that here? Well that's besides the point. I finally decided that it was too long, I wanted to see my famous son I always heard so much about from other people. I wanted to hear about his life from him. So I came out of hiding and found you. And now, we will be able to share our lives again."
Harry was very taken aback by what the strange man--no, he shook himself--his Dad had said. But he took him seriously. If Dumbledore believed him, then Harry would too. Suddenly, Harry felt a surge of love, sorrow, worrying, every possible emotion surging in to his body. It was taking over his heart and his brain. So this is what it feels like to have a father, he thought. So he ran over and hugged him. He hugged his father. He had a father. He felt like screaming at the top of his lungs. Look at my Dad!!! he wanted to yell it from the highest Hogwarts tower.