Transcript for Author AJ Jacobs on How We're All Related
We turn to one man's quest to show how we're one big family. Best-selling author A.J. Jacobs is creating the biggest family tree. Sara Haines has the story. Reporter: What if I was related to Channing Tatum or Kate Middleton or Denzel. Could it be? Is it possible as I look around I'm related to everyone here? Not possible, it's true. Absolutely -- Reporter: Meet A.J. Whose goal is to throw the world's biggest family reunion right here in New York and says even he and I are related. A mere 31 steps away. Yep, A.J. Is my fourth great uncle's great daughter's nephew. You got it? You're connected through -- The ziegenthuse. My grandmother's maiden name. You have to come to the global family reunion. We want to get the word out about it so cousin amg and I sat out to try to meet and invite family minimums. You have 77 million cousins. Two new cousins. Welcome to the family. A.j.'s family tree has over 77 million leads and continues to grow. Here I am and then just 23 relatives away there's George stephanopoulos, people say that they don't feel alone anymore. They feel connected. I'm Daniel Radcliffe and A.J. Jacobs and he's my cousin and we are probably cousins. Reporter: Even though his own family claims two American presidents, not everybody is impressed. Tory, it's your cousin A.J., we're just 17 steps away. It's your cousin through the donskis. With more than 77 other relatives maybe no one will notice she's not at the reunion. For "Good morning America," Sara Haines, ABC news, New York.
This transcript has been automatically generated and may not be 100% accurate.