US President Joe Biden has appointed Philip Reeker as temporary chargé d’affaires to the UK.
Mr Reeker replaces Yael Lempert, who was appointed to the same role in January when Mr Biden became president.
A permanent ambassador to the UK has yet to be found, with no clear front-runners in place. Mr Biden is said to favour someone with considerable diplomatic experience.
Donald Trump’s “Man in London”, Woody Johnson cleared his desk on January 20 after four years in the role. He signed off by posting a picture of himself with Queen Elizabeth.
The US Embassy said: “The United States has no closer ally than the United Kingdom, and Ambassador Reeker is dedicated to continuing to advance this special relationship.”
Mr Reeker will take up his role on August 1.
A career diplomat with the rank of minister counsellor, he is currently the acting assistant secretary of state for the Bureau of European and Eurasian Affairs.
Previously, he was civilian deputy and policy adviser to the commander of the US military’s European Command in Stuttgart, Germany, and from 2008-2011 he was the US ambassador to North Macedonia.
Speculation on candidates has included Bob Iger, the executive chairman of Disney, James Costos, who was Barack Obama's ambassador to Spain, Anthony Luzatto, a former ambassador to the EU, and Ted Kaufman, a former senator who was once Mr Biden’s chief of staff.