For me it was Jeff Kinney. I was meeting a different author I love, but there wasn't enough room downstairs and we had to go up. Turns out that's exactly where Jeff Kinney works! He's the author who got me into reading so I thought that was so cool
They always spend like an hour in the hallways outside the Penn and Teller Theater after shows meeting fans. The people who crowd around Teller are often magicians because he is notoriously generous when it comes to helping other magicians. They both are really, but I think a majority of successful magicians in the US have a trick in their repertoire that Teller helped out with in some way or another.