President Donald Trump has named Rep. Mark Meadows as his new chief of staff, replacing Mick Mulvaney, who been acting in the role for more than a year.

Trump announced the staff reshuffle in tweets, saying Mulvaney would become the U.S. special envoy for Northern Ireland.

“I am pleased to announce that Congressman Mark Meadows will become White House Chief of Staff. I have long known and worked with Mark, and the relationship is a very good one. I want to thank Acting Chief Mick Mulvaney for having served the Administration so well. He will become the United States Special Envoy for Northern Ireland. Thank you!”

The long-rumored move makes Meadows effectively Trump’s fourth chief of staff since taking office in 2017.

The decision comes as the Trump administration has faced criticism for its handling of the novel coronavirus outbreak. Mulvaney had been leading the interagency response to the virus until Trump designated Vice President Mike Pence to lead the whole-of-government effort more than a week ago.

The Associated Press contributed to this story.