The GOP presidential candidates will face off Thursday in their final debate before next week's Iowa caucuses -- this time, without Donald Trump.

Fox News, which is hosting the event, announced on Tuesday which candidates made the cut for the primetime debate at 9 p.m. ET.

The candidate lineup for the 9p ET Fox News-Google #GOPDebate on Thursday, January 28th: pic.twitter.com/OO6ExOojvt

— Fox News (@FoxNews) January 26, 2016

In a shift from the last debate earlier this month, Sen. Rand Paul (R-Ky.) will be on the main stage. Paul's flagging poll numbers dropped him to the "undercard" debate, which he chose to skip in protest. 

Trump's campaign manager Corey Lewandowski confirmed to the Washington Post on Tuesday that the GOP front-runner is "definitely not participating in the Fox News debate."

Earlier in the day, Trump teased he "most likely" will not participate, stemming from his ongoing feud with Fox News anchor and debate moderator Megyn Kelly.

At the network's last debate in August, Trump protested Kelly's questions about his sexism and misogyny and launched a series of offensive attacks against her, which included suggesting that she asked him pointed questions because of menstruation.

On Tuesday, the real estate mogul continued to attack Kelly, calling her "a third-rate reporter" and a "lightweight."

Carly Fiorina, Rick Santorum, Mike Huckabee and Jim Gilmore will participate in Thursday's "undercard" debate, beginning at 7 p.m. ET. It's the first debate appearance for Gilmore since the very first GOP debate this summer.