Telltale signs of emerging hit TV series, such as USA Network's new, offbeat drama "Monk," typically are celebrity guest shots or cameos. But in the case of "Monk," it also helps that noted filmmaker and series producer David Hoberman has his connections.

Such was the case when filmmaking buddy Garry Marshall did a tour de force guest shot as an extension cord salesman who is stuck seated next to the obsessive-compulsive detective Adrian Monk (Tony Shalhoub) in the show's season finale that aired last Friday.

As it turns out, Mr. Hoberman is currently in pre-production on a new motion picture, "Raising Helen" (starring Kate Hudson), which has Mr. Marshall attached as director.

"Garry and I were in a [pre-production] meeting when all of the sudden he says, '"Monk" is my wife's favorite show,'" related Mr. Hoberman. "He then said, 'Whenever you have a part, I'd love to do it.' To have Garry Marshall seated in an airplane next to Tony when he's going through his germophobic fits and fear of flying was just too hysterical to describe while we were in production."

At one point in the episode, a flight attendant played by Mr. Shalhoub's wife, actress Brooke Adams, angrily chastises the "defective detective" for lighting a lighter in violation of federal aviation regulations. "I think it was just a case where Tony had been in Toronto for so long shooting the show, he missed his wife and asked for a part so he could see her," Mr. Hoberman said with a laugh.

On the previous episode, Mr. Hoberman turned to his agent, Jim Wiatt of William Morris Agency, to get fellow client and country singer Willie Nelson to play himself as potential murder suspect. Of course, Mr. Nelson ended up being acquitted by the unflappable Monk.