LOS ANGELES — Chris Rock, the actor and comedian, headlined the Hollywood wiretapping trial on Friday, fully inhabiting the role of a witness who found absolutely nothing funny in being called to testify.
Dressed in black and speaking mostly in hushed monosyllables, Mr. Rock described himself as the victim of a 1999 shakedown attempt by a model who he said had falsely accused him of paternity.
He acknowledged having hired Anthony Pellicano, the private detective on trial here for wiretapping and racketeering, to investigate her. And he confirmed the authenticity of a lengthy phone call in which he and Mr. Pellicano discussed the woman — a call that Mr. Pellicano secretly recorded and the F.B.I. later seized.
Mr. Rock’s 15-minute standing-room-only appearance, including cross-examination, was the first and most likely the only one in the trial by a star still at the top of his entertainment career.
It led off a day when jurors also heard extended testimony about illegal work by Mr. Pellicano on behalf of two billionaires — Alec Gores, a Los Angeles investor, and Taylor Thomson, a Canadian media heiress — neither of whom has been prosecuted.
Like other former Pellicano clients with boldface names or entries on the Forbes list, Mr. Rock was treated gingerly by prosecutors, though his put-upon look and almost surly tone did not suggest gratitude.
They did not ask him to describe the extramarital affair that led to a paternity claim by the model, Monika Zsibrita; they did not ask about the details of her accusation that he had assaulted her sexually (no charges were ever brought); and they did not play even a one-minute excerpt of the recorded call until Mr. Rock had left the courtroom along with his small entourage.
Taking the stand at 8:05 a.m., Mr. Rock gave his name so quietly that Judge Dale S. Fischer admonished him, saying: “Mr. Rock: project!”
But the assistant United States attorney, Daniel A. Saunders, did not ask his occupation, a note of deference not shown to the comedian Garry Shandling or the actor Keith Carradine earlier in the trial.
Mr. Saunders instead briskly led Mr. Rock through 25 questions, highlighting evidence that Mr. Pellicano had paid a police officer, Mark Arneson, to run illegal checks of the criminal and motor-vehicle histories of Ms. Zsibrita and of a friend of hers, who Mr. Pellicano suspected was her child’s biological father.
Mr. Rock’s replies scarcely exceeded “yes,” or “no.” On cross-examination, Mr. Arneson’s lawyer, Chad Hummel, gave Mr. Rock the opportunity to describe Ms. Zsibrita’s effort to shake him down, asking if he thought her claim was false.
“I didn’t believe the claim was false; DNA tests proved the claim was false; so this was not a ‘belief’ of mine,” Mr. Rock said. “Someone who was not pregnant with my child claimed to be pregnant with my child, and requested large sums of money for this.”
Asked by Mr. Hummel about the assault claim, Mr. Rock said: “I’m here as a free man, and I didn’t do anything. You know I didn’t do anything.”
After Mr. Rock’s exit, Mr. Gores, a wealthy buyout executive, took the stand and testified to having hired Mr. Pellicano in December 2000 to confirm his suspicions that his wife then, Lisa, was having an affair with his brother, Tom Gores. Mr. Gores said he paid Mr. Pellicano nearly $300,000, plus an all-expenses-paid Hawaiian vacation for his family, for his work.
The Gores case is important because prosecutors have introduced only one recording that they say is an actual telephone intercept: a call between Lisa and Tom Gores after a rendezvous at the Beverly Hills Hotel.
Another colorful witness Friday was Pamela Miller, once the nanny for Ms. Thomson, heir to the Thomson media fortune. Still simmering, Ms. Miller said she was fired in April 2002 — and that Mr. Pellicano investigated her illegally — after she gave an affidavit to the father of Ms. Thomson’s toddler daughter to help him in his custody fight.
For example, Ms. Miller recalled, she had been told not to feed carbohydrates to the 18-month-old girl because “the mother wanted her to be very thin.”
In a recording made days after her affidavit and played in court, Ms. Thomson could be heard telling Mr. Pellicano to do whatever it took. “I’m not going to ask any questions,” she said. “If you need information, just get the information.”