The segment won't air, but an audience member walked up to Colin Farrell in the middle of the taping of "The Tonight Show." She said something to him audience members couldn't hear and then he led her off stage and to security. He returned to the set, joked about it and then stayed for the rest of the show. The woman was not arrested, "per the request of NBC." That presumably means Farrell didn't want her arrested. But why the hell not? Scary -- you look at the security at talk show tapings or the Tour de France (where people are literally within arms reach of the competitors) and you can't help but be amazed that a lot more terrible things don't happen every day.
UPDATE: Now IMDB is reporting the woman is the person who claimed Farrell was stalking HER last year. Uh, kind of pokes holes in your argument when you seek him out in public and interrupt the taping of a tv show in front of hundreds to make a scene. Perhaps NBC chose not to prosecute her after speaking to his lawyers. At the very least he should now get a restraining order.