Story highlights Ben Carson will endorse Donald Trump on Friday, multiple sources told CNN

Trump has a press conference scheduled for 9 a.m. ET in Palm Beach, Florida

(CNN) Former presidential candidate Ben Carson will endorse Donald Trump, the real estate mogul said Thursday during the GOP presidential debate hosted by CNN, handing Trump an important boost heading into next week's "Super Tuesday 3."

Carson, a retired neurosurgeon, ended his own White House campaign last week after failing to win a single primary contest. Trump is scheduled to hold a press conference Friday at 9 a.m. ET at the Mar-a-Lago club in Palm Beach, Florida. During the debate, Trump answered a question related to education by adding that Carson is "endorsing me, by the way, tomorrow morning."

The endorsement was first reported by The Washington Post.

Carson, respected within the evangelical community, had briefly overtaken Trump in the polls earlier in the 2016 campaign. But he failed to maintain that momentum as he struggled with foreign policy and national security questions and made multiple gaffes on the trail.

Speaking to CNN's Erin Burnett on Thursday night, Republican National Committee Chairman Reince Priebus said he didn't know all the details about the endorsement.

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