"A horse walks into a bar, and the bartender says, 'Why the long face?'"

Rainn Wilson was telling the audience his favorite joke Thursday at Barnes & Noble in Bella Terra. "The Office" actor had come to talk about his spiritual book, "SoulPancake: Chew on Life's Big Questions," but it was only a matter of time before comedy entered the discussion. An audience member asked Wilson, who plays Dwight Schrute, to give them his favorite gut-buster.

"I never get tired of that joke," Wilson said. "But I put my own twist on it: A horse walks into a bar, and the bartender says, 'Why the long face?' And the horse says, 'Pancreatic cancer.'"

Earlier in his presentation, and in the foreword of "SoulPancake," Wilson had insisted that he and Dwight were not the same person. But at that moment, they seemed to intertwine, if just a bit. Anyone who, like me, knows "The Office" by heart should have no problem picturing Dwight, with his glasses and sternly parted hair, delivering that joke to the camera with a defiant smirk.

Those are the two competing emotions when seeing celebrities up close. On one hand, you can see that they're just a person like everyone else when they step out of character. On the other hand, you're still seeing a celebrity up close, and if you get to do neat things like hand him your business card and give them a copy of the Independent that has your story in it — well, your self-image will thank you in the morning.

Furthermore, if the celebrity is the guy who plays Dwight, that means you're one degree of separation from the woman who plays Pam. 'Nuff said.

But back to the event. Wilson, who describes himself as an intensely spiritual person, created a website, "SoulPancake," to encourage people of all faiths to talk about God and philosophy. Out of that website grew his book, which features a lengthy foreword by Wilson, art and essays by other contributors, and sections in which the reader is invited to pencil in observations.

Wilson told me over the phone last week that when he has a "SoulPancake" signing, he's often besieged with "Office" questions. At Barnes & Noble, though, much of the discussion really did revolve around philosophical matters. The actor, wearing a leather jacket and sporting a stubbly beard, talked about his lost days as a young man and his need to seek truth outside of organized religion.

"We live philosophy," Wilson told the crowd of people who surrounded the stairs on the upper level. "It's a living, breathing thing."

At one point, an audience member asked Wilson if he ever tired of being associated with Dwight. He replied that he didn't, that he was happy to be able to act for a living and to have a character that amused so many people. He noted, though, that he viewed his work as part of a greater spiritual quest, and one that he didn't always perceive among Hollywood peers.

"You'll be amazed how many unhappy actors there are in the world," Wilson said. "There's an old joke: What do you do to make an actor unhappy? Give him a job."

When Wilson finished speaking, I stepped over to the signing table and shook his hand, then asked if he would sign my copy of "SoulPancake" before the crowd descended. He scribbled his name on the title page, then, in lieu of a message, drew a single question mark by the phrase "Life's Big Questions."

My spiritual quest goes on, and I thank Dwight for pointing the way.

City Editor MICHAEL MILLER can be reached at (714) 966-4617 or at michael.miller@latimes.com.