Tom Hanks is the most trusted celebrity while NBC's Brian Williams took a nosedive in trust ratings, the Celebrity DBI by The Marketing Arm revealed.

The Celebrity DBI is an independent, global index that ranks celebrities' ability to impact consumers, and Hanks was hailed as the most influential, followed closely by Duchess Kate Middleton, Dr Lisa Masterson, Morgan Freeman, and Chesley Sullenberger.

TV broadcaster Robin Roberts also ranked high at No. 11, Ann Curry is No. 32, Dr. Sanjay Gupta is No. 62, ABC's Diane Sawyer is No. 127, Tom Brokaw is at No. 139, and CNN's Anderson Cooper is No. 179.

On the flipside, disgraced anchor Williams went from being No. 23 down to No. 835 on the list of most trusted people since news broke out that he apparently fabricated his Iraq reports.

"We haven't seen a drop like this since Tiger Woods," The Marketing Arm New York managing director Robert Familetti told TVNewser.

Williams is now in the company of Duck Dynasty star Willie Robertson at No. 815, whereas before his trust rating was held high and considered equal to that of Denzel Washington, Warren Buffett, and Oprah Winfrey.

Fellow anchor Dan Rather also ranked low at No. 924, while CBS Evening News host Scott Pelley ranked at No. 791. ABC's World News Tonight anchor David Muir did not make the list this time, but he is expected to be included in the next edition.

The results of the Celebrity DBI are used by brands, agencies, professional teams, leagues and marketers to determine if a celebrity is brand relevant. The list is updated at several times, depending on a celebrity making news or or the list becoming "outdated."

Karen Cerulo, a sociology professor at Rutgers, told The New York Daily Times that Williams can still turn his situation around by offering a more sincere apology. "Successful apologies need to begin by focusing people on the victim, not the sinner," she said.

She added that Williams should offer statements of remorse and corrective action, but so far the news anchor has kept a low profile.