"I think they've tapped into something, and you almost can't believe what you're hearing is really written," Shields said.
Pack agreed: The words speak for themselves.
"You don't have to do that much and let the audience react," he said.
He said most celebrity books start with an over-the-top prologue and end with banal lists, because the star has "run out of things to say."
Pack does a reading from singer Neil Sedaka's "Laughing in the Rain," in which he lists what he eats at every meal.
Most celebrities don't seem to mind the send-ups of their books. Like Shields, they've even offered up their books to be read.
Pack, who also performs a monologue from George Takei's book, "To the Stars," said the "Star Trek" star came to see the show.
"He was on the floor laughing," he said.
For now, there seems to be no shortage of material.
"I don't think you can run out of material," Pack said. "Basically, if you're a celebrity, you're required to write a book."