Donald Trump is expected to announce South Carolina Governor Nikki Haley as his ambassador to the UN.
Ms Haley, 44, has reportedly accepted the President-elect's offer to serve in his administration, which would make her the first woman appointed to his cabinet.
The Republican governor is currently serving her second term, and has worked on trade and labor issues, but is said to have little foreign policy experience.
Her views on various US military and national security matters are reportedly in line with the party mainstream.
If confirmed, Ms Haley will be replaced in her current role by Henry McMaster, a top Trump ally. A source said the move was seen inside Mr Trump's inner circle as a way to promote them both.
Ms Haley, who is the daughter of Indian immigrants, has been critical of some of Mr Trump's proposals in the past.
She has been described as the establishment’s choice to represent a sensible side of Republicanism, directly contrasting the controversial President-elect.
When she delivered the Republican response to the State of the Union address at the start of the year, Ms Haley appeared to take a swipe at Mr Trump.
“Today we live in a time of threats like few others in recent memory,” she said. “During anxious times, it can be tempting to follow the siren call of the angriest voices. We must resist that temptation.”
She also defended Muslims and legal immigration in the speech.
However, Ms Haley has been accused of trafficking right wing conspiracy theories in the past, linking President Obama to riots in Ferguson, Missouri, and Baltimore, and contrasting these events with her handling of shootings by citizens, rather than police, in South Carolina.
“Our state was struck with shock, pain and fear. But our people would not allow hate to win,” Ms Haley said, of a massacre which killed nine people at a Church in Charleston in June 2015.
“We didn’t have violence; we had vigils," she said. "We didn’t have riots; we had hugs."
Despite their differences, when Ms Haley visited Mr Trump last week, she told reporters that she had never disliked him.
“He was a friend and supporter before he ran for president, and was kind to me then. But when I see something I am uncomfortable with, I say it,” she said.
“When we met, it was friends who had known each other before.”
