The next showdown is set to take place on 8 November at the Adrienne Arsht Center for the Performing Arts in Miami.
Mr Holt, 64, co-moderated the first debate in the 2020 Democratic primaries and he was the sole moderator in the first 2016 general election debate between Mr Trump and former Secretary of State and New York Senator Hillary Clinton.
He worked for CBS between 1981 and 2000, at which point he joined NBC. He took the anchor chair of NBC Nightly News in 2015 following the departure of Brian Williams. Mr Holt then became the first African American to be the sole anchor of a weekday network nightly newscast.
Ms Welker, 47, NBC’s co-chief White House correspondent, was appointed as the new moderator of Meet The Press, NBC’s flagship Sunday political talk show and longest-running TV programme ever, on 17 September.
Ms Welker was criticised for her handling of former President Donald Trump during an interview earlier this year but praised after her performance moderating one of the 2020 general election debates between Mr Trump and then-candidate Joe Biden.
“Think we can all agree the winner is Kristen Welker,” said Jimmy Fallon, the host of NBC’s Tonight Show.
Mr Hewitt, 67, served in the Reagan administration in a number of positions, after which he worked at the Nixon Library before becoming a radio host in the 1990s. The Hugh Hewitt Show is nationally syndicated and Mr Hewitt is also a Washington Post columnist.
Mr Hewitt clashed with Mr Trump on several occasions when hosting events during the 2016 campaign, once saying that he didn’t have “the temperament to be president”. He also said that the GOP failing to see the consequences of Mr Trump becoming the nominee would be similar to “ignoring Stage IV cancer”.
To qualify, candidates need to reach at least four per cent in two national polls, or four per cent in one national poll and four per cent in two early primary states.
They also need 70,000 individual donors, including 200 donors in 20 states, according to the requirements set by the Republican National Committee (RNC).
Five candidates have qualified for the showdown, so far – Florida Governor Ron DeSantis, biotech entrepreneur and woke-bashing author Vivek Ramaswamy, former UN Ambassador and South Carolina Governor Nikki Haley, and ex-New Jersey Governor Chris Christie.
Former President Donald Trump has also qualified but has said that, like the first two debates, he won’t attend. He will instead hold a rally in Hialeah, Florida, not far from Miami.
While former Vice President Mike Pence has reached the required polling results to participate in the debate, he still needs to acquire 70,000 individual donors.
South Carolina Senator Tim Scott has hit the required polling in two state polls but hasn’t reached the threshold in national polling or when it comes to donors, according to Politico, even as his campaign argues they have hit the required polling and is on track to get the number of donors needed.
The qualification period is 1 September to 6 November.