President Trump is set to nominate Richard Grenell, a veteran Republican foreign affairs spokesman, to serve as ambassador to NATO, several news outlets reported Wednesday.

Grenell is an outspoken Trump supporter who served as a spokesman for John Bolton, former U.S. ambassador to the United Nations, and several other GOP-appointed U.N. ambassadors.

An openly-gay Republican, Grenell would be one of the highest-ranking gay members of the Trump administration.

An official said Wednesday morning that the White House could not confirm the appointment of Grenell.