A.J. Jacobs (left) and Daniel Radcliffe
Courtesy AJ Jacobs
Best-selling author A.J. Jacobs
is on a mission to trace his family tree and track down distant relatives – and map out how we're all related.
Every month until June 6, 2015, when he's throwing a massive family reunion (go to globalfamilyreunion.com
to join), the author will chat with one of his famous "cousins" for PEOPLE.
This month's relative? What If star
– and recent birthday boy
– Daniel Radcliffe
How are we related, exactly?
You are my first cousin once removed's husband's third great aunt's husband's fourth cousin twice removed's wife's second cousin's brother-in-law's sister-in-law's son-in-law's brother's great-grandson.
So in a word, cousins.
I know you have a crush on Katy Perry
. Guess what – you're related. And Albert Einstein and a lot of the British royalty. I'm not British, so it doesn't resonate with me that much.
It doesn't really resonate with me that much either. I'm more excited about Einstein, to be honest.
What is the best bit of family wisdom you've gotten?
I'd come whine about something that happened on the set, and my dad would say, "You're not down in a coal mine." It's a very good way of putting things into perspective.
Do you want to make the family tree bigger by having little Radcliffes?
Maybe because I'm an only child, I love the idea of lots of kids. But it will depend to a larger part on who I end up having kids with. I think men would be a lot less excited about having kids if we had to actually do it!
For more of Jacobs's interview with Daniel Radcliffe, pick up the July 28 issue of
PEOPLE, on newsstands now