Heather Nauert whgo could be UN Envoy, did not immediately respond to request for comment.
In addition to that role, Ms Nauert was appointed acting undersecretary for public diplomacy and public affairs in March this year. The officials were not authorized to speak publicly before Trump's announcement.
Ms Nauert started her career as a reporter for CBS News, before co-hosting Fox News morning show "Fox & Friends", of which President Trump is known to be a frequent viewer.
Numerous reports in the USA media - the first of which appeared in Bloomberg news - said Nauert would be nominated Friday, citing sources close to the matter.
Ms Nauert is described by United States media as an "unorthodox choice" for the role due to her little experience in government or foreign policy. She had no government or foreign policy experience prior to joining the Trump Administration.
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Heather Nauert, who earlier this year had been considered a possible successor to White House spokeswoman, Sarah Sanders, gained experience on diplomacy by working at the State Department, but she lacks the political and policy credentials of Ms Haley, who is a former governor of SC.
When Trump named her as his to become ambassador to the United Nations, it came as a surprise to many.
She will need to win Senate confirmation to assume the role.
The president considered Nauert for the position among a list of potential nominees that included former White House aide Dina Powell and ambassador to Germany Richard Grenell.
"She is clearly not qualified for this job, but these days it seems that the most important qualification is that you show up on Donald Trump's TV screen, and if you're successful in that endeavor, then you seem to be a top candidate to get a whole bunch of top positions in the USA government".
Although some have speculated that Haley may challenge Mr. Trump in 2020, Haley has said that she will support the president.