President Trump has chosen Heather Nauert to replace Nikki Haley as U.S. ambassador to the United Nations, three sources with knowledge of the decision told CBS News. Nauert is currently the spokeswoman for the State Department. Nauert has been on the short list for ambassador to the U.N. since Haley announced that she was stepping down from her post in October. Formerly a Fox News anchor, she came to the administration in 2017. She will have to be confirmed by the Senate to become ambassador to the U.N. Nauert’s appointment was first reported by Bloomberg. Although some have speculated that Haley may challenge Mr. Trump in 2020, Haley has said that she will support the president. “I can promise you what I will be doing is campaigning for this one. So I look forward to supporting the president in the next election,” Haley said at a press conference while sitting next to Mr. Trump. CBS News’ Major Garrett and Fin Gomez contributed reporting.