The "Late Show" host, who largely based his "Colbert Report" conservative pundit persona on the former Fox News anchor, kicked off Wednesday's show by devoting much of his opening monologue to the news of O'Reilly's ouster from Fox News amid sexual harassment allegations.
The popular host was in St. Peter's Square with his son for Pope Francis' weekly address, and afterwards stood in a VIP line to shake hands with the holy leader.
Yesterday 21 Century Fox, which owns the Fox News Channel, announced O'Reilly had been dropped.
The firing followed a New York Times investigation that uncovered $13 million in settlements paid out to five women in exchange for agreeing to not speak out or pursue litigation regarding allegations of sexual harassment against O'Reilly.
But after the New York Times report, advertisers including BMW of North America, Allstate Corp, French pharmaceuticals maker Sanofi SA and T. Rowe Price, pulled their advertising from O'Reilly's primetime "The O'Reilly Factor" show.
Fox News is cutting ties with Bill O'Reilly, the biggest star in its 20-year history, after mounting allegations of sexual harassment and inappropriate behavior prompted the network to end his program.
Powers said she quit O'Reilly's show, but returned three years later.
After almost two decades as Fox News' most popular host, Bill O'Reilly, 67, was let go Wednesday by parent company 21st Century Fox. "I wish only the best for Fox News Channel".More news: Cannabis Act: Canada set to legalise marijuana to keep children 'safe'
"But it is the unfortunate reality that man in the public eye must live with today", O'Reilly said.
"I will always look back on my time at Fox with great pride in the unprecedented success we achieved and with my deepest gratitude to all my dedicated viewers".
For O'Reilly, who has been with Fox since October 1996, it marks a stunning downfall.
"I understand how hard this has been for many of you", Rupert Murdoch said in the memo. "He set the agenda and formed opinions".
Fox News did not respond to a request by Deadline for comment from Deadline on Smith's statement. "Fox News should have fired him in 2004 when (former Fox News producer) Andrea Mackris spoke out, but at least they did it now", she said.
Not even the support of Trump - himself caught boasting of groping women and saddled with record-low approval ratings - was enough to right the ship for O'Reilly. FILE - In this October 1, 2015 file photo, host Bill O'Reilly of "The O'Reilly Factor" on the Fox News Channel, poses for photos in the set in NY. "When you hear the phrase 'fair and balanced news, ' it was O'Reilly you thought about". Eastern slot by Tucker Carlson, who moved to the channel's prime-time lineup only in January.
Carlson's current 9 p.m. slot will be filled by the panel talk show "The Five", which will be replaced at 5 p.m. with a new show hosted by Eric Bolling, now a co-host of "The Five" and a frequent fill-in host on "The Factor".