DeSantis and Newsom will debate, with Sean Hannity moderating

Florida Republican Gov. Ron DeSantis and California Democratic Gov. Gavin Newsom will debate one another on Thursday night in an event being billed as a clash of "red vs. blue state" -- and a test of rising stars in their respective parties.

After months of teasing it, DeSantis and Newsom will finally face off in the battleground state of Georgia for a 90-minute debate moderated by Fox News' Sean Hannity that starts at 9 p.m. EST.

Topics will include inflation, crime, the economy, the border and other "major issues impacting the country," according to the network. "The debate will examine the vastly different approaches the two governors have and offer insights into their political philosophies as well as ambitions for the nation."

The debate comes after months of planning and wrangling over the rules. It will amplify the ongoing rivalry between the governors of two of the country's largest states, who have gone after each other over the past couple of years.

DeSantis has contended Newsom is responsible for a decline in California, explicitly calling out Newsom's handling of the COVID-19 pandemic, public safety, the state's housing supply and homelessness.

Newsom has been no less fierce in criticizing DeSantis, initially challenging him to a debate over a year ago. In an interview with NBC News in September, Newsom said he believes DeSantis is "functionally authoritarian."

Newsom has upped his attacks against DeSantis leading up to the debate. Most recently, the Newsom-aligned super PAC, Campaign For Democracy, launched an ad assailing Florida's six-week abortion ban, which DeSantis signed into law.

In the ad narrated, by the California governor, Newsom said the abortion ban is "not freedom" but "DeSantis' Florida." DeSantis has defended the ban as "support[ing] life and family."

The debate performance of both governors will likely fuel further speculation about their political futures. DeSantis is running for the White House, but his initial strength in the primary polls has faded and he continues to trail former President Donald Trump by double digits.

Newsom has been floated as a potential presidential candidate in 2028, as he is termed limited from running for governor again.

Newsom has also been a vocal ally of President Joe Biden and acted as a campaign surrogate for him over the past few months, including participating in the spin room following the second GOP primary debate, providing the Democrats' response.

"Expect him to defend the President and use the opportunity to take on the misinformation machine at its headwaters," Nathan Click, a spokesperson for Newsom, told ABC News when asked what viewers should expect from the governor on the debate stage on Thursday.

As for DeSantis, his campaign views this debate as their most important one yet, hoping to "contrast" the Florida governor with Newsom, claiming he’s a possible replacement for Biden in the 2024 race, which Newsom has repeatedly dismissed.

"Ron DeSantis will take this responsibility seriously and looks forward to sharing the stark contrast between his vision to revive our nation and Newsom's blueprint for failure," DeSantis' campaign manager, James Uthmeier, told ABC News in a statement.

The Biden campaign said they welcomed Newsom's support "as he forcefully and effectively makes the president’s case," TJ Ducklo, a senior communication adviser on the Biden campaign, told ABC News in a statement.

"We look forward to him highlighting how Ron DeSantis' extremism and failures in Florida are part of a MAGA agenda we cannot allow back in the White House," Ducklo said.