[Flashback to Booth and Brennan's first case]
Booth: Listen, I've got something to confess.
Brennan: Is it the fact that you're a direct descendant of John Wilkes Booth? I already know that.
Booth: Wait, wait a second. How do you know that?
Brennan: From your bone structure.
Booth: Keep that under your hat for now, okay?
Brennan: [laughs] Okay.
Booth: Listen, I've got something to confess.
Brennan: Is it the fact that you're a direct descendant of John Wilkes Booth? I already know that.
Booth: Wait, wait a second. How do you know that?
Brennan: From your bone structure.
Booth: Keep that under your hat for now, okay?
Brennan: [laughs] Okay.
[Flashback to Booth and Brennan's first case]
Booth : Listen, I've got something to confess.
Brennan : Is it the fact that you're a direct descendant of John Wilkes Booth? I already know that.
Booth : Wait, wait a second. How do you know that?
Brennan : From your bone structure.
Booth : Keep that under your hat for now, okay?
Brennan : [laughs] Okay.
http://www.tv-quotes.com/shows/bones/quote_21870.html