NEW YORK >> Fox News Channel is giving Megyn Kelly’s time slot to veteran pundit Tucker Carlson, doubling down on conservative opinion leaders in its prime-time lineup at the dawn of the Trump administration.

The network also said on Thursday that Martha MacCallum will move into Carson’s 7 p.m. time slot, at least temporarily. She will host a show called “The First 100 Days” to coincide with the beginning of Donald Trump’s presidency.

Carlson, who has hosted shows on CNN, MSNBC and PBS, replaced Greta Van Susteren, who left Fox in late summer. Since his start on Nov. 14, the average audience of 2.8 million viewers for “Tucker Carlson Tonight” is up 23 percent compared to Van Susteren a year ago, the Nielsen company said.

“In less than two months, Tucker has taken cable news by storm with his spirited interviews and consistently strong performance,” said Rupert Murdoch, executive chairman of Fox News and its parent company 21st Century Fox.

Fox can argue that Carlson gives the network its best chance to maintain, or even build upon, Kelly’s ratings. Kelly turned down a multi-million dollar offer to stay at Fox and announced this week she will leave for NBC News, where she will host a daytime weekday show and a once-a-week newsmagazine on Sunday nights. While the most recent campaign made her a star, her sharp questioning of Donald Trump during debates upset the candidate, his supporters, and many Fox viewers.

Carlson’s selection sends a political signal, said Jane Hall, a journalism professor at American University in Washington and a former panelist on a Fox media watch program.

“Their prime-time hosts are going to be aggressively conservative in the way that Donald Trump and his supporters have been,” Hall said.

Carlson, 47, will be sandwiched between Bill O’Reilly, who has long been the top-rated host in cable news, and Sean Hannity, who has been outspoken in his advocacy for Trump.

He’s no stranger to the pundit wars. He began his TV career at CNN, where his role as a “Crossfire” host memorably imploded in 2004 when comedian Jon Stewart questioned the show’s value and the segment sunk into name-calling. Three months later, CNN got rid of “Crossfire” and Carlson.

He surfaced at MSNBC for an early evening show. He joined Fox as a contributor in 2009 and founded the conservative web site The Daily Caller, where his involvement ended when he began the daily show at Fox.

Perhaps the most memorable segment on “Tucker Carlson Tonight” came when the host went toe-to-toe with Lauren Duca, a Teen Vogue writer brought on to discuss an incident where Ivanka Trump was approached by someone who objected to her dad’s politics on a plane flight with her family. The segment spread widely online and Duca later said she received rape threats on Christmas Day.

“Tucker Carlson’s brand is a toxic mix of blowhard condescension, partisan hackery and unbridled sexism,” Duca said on Thursday. “It only makes sense that he would excel at Fox.”

Television executive Rick Kaplan, who hired Carlson at both CNN and MSNBC, said he found Carlson easy to talk and listen to even when he disagreed with him politically.

“He’s an exceptional, exceptional communicator,” Kaplan said. “He clearly has a partisan stripe, but he’s kind of gentle reader. He’s an honest broker, he’s a fair guy. He’s not a mean guy, so I find him extremely pleasing to watch.”

Carlson begins on Monday. MacCallum starts at 7 p.m. the following week, after Bret Baier fills in for a week. A former anchor at CNBC, the 52-year-old MacCallum has been with Fox since 2004 and currently co-hosts a two-hour news block with Bill Hemmer on weekday mornings.

She will co-anchor Fox’s inauguration coverage with Baier later this month, taking over a role that Kelly would have been expected to fill.

Her evening show keyed to the beginning of the Trump administration is something of a tryout, though. Fox is not committing to what goes into the time slot after the first 100 days.