President Donald Trump has tapped Mike Waltz to be the U.S. ambassador to the United Nations after ousting him as National Security Adviser.

The shake-up comes just weeks after the Signalgate scandal, where Waltz inadvertently added a journalist from The Atlantic into a chat discussing war plans in Yemen.

Trump announced the move in a post on Truth Social Thursday afternoon after reports of Waltz’s departure broke.

“I am pleased to announce that I will be nominating Mike Waltz to be the next United States Ambassador to the United Nations,” Trump said in the post. “From his time in uniform on the battlefield, in Congress and, as my National Security Advisor, Mike Waltz has worked hard to put our Nation’s Interests first. I know he will do the same in his new role.”

The president added that Secretary of State Marco Rubio will pick up Waltz’s former role in the interim, while continuing to head up the State Department.

The ambassador role requires Senate confirmation.

It was reported earlier Thursday by CBS News and CNN that Waltz and his deputy, Alex Wong, would be leaving their roles.

It was “made clear” to Waltz earlier this week that “his time leading the National Security Council had come to an end,” CNN reported. Questions swirled about Waltz’s role after it was revealed that he added the journalist Jeffrey Goldberg into a chat on the Signal app detailing military strikes. The chat involved high-ranking military and administration members and news of the breach became a blunder for the White House.

Trump publicly backed Waltz after the Signalgate scandal broke and said he was “a very good man.”

White House Press Secretary Karoline Leavitt also reiterated in a statement at the time that the president “has the utmost confidence in Mike Waltz and his entire national security team.”

Waltz said he took responsibility for the gaffe at the time. “I take full responsibility. I built the group,” Waltz said. “It’s embarrassing. We’re going to get to the bottom of it.”

Trump said Waltz had “learned his lesson” and would not be fired. The president also blamed sharing the messages on an error from “one of Michael’s people” that did not amount to a “serious” issue.

Sources told CNN that Waltz “never really recovered” from the Signalgate scandal.

Democratic Senator Mark Kelly reportedly told the network that the Trump administration “has the wrong guy,” and pointed the finger at Defense Secretary Pete Hegseth, who shared messages with details of the plans.

“I think they’re holding the wrong guy accountable … I think they fired the wrong guy,” Kelly told CNN.

Waltz appeared on Fox & Friends Thursday morning hailing Trump’s minerals deal with Ukraine just hours before his departure was reported. At yesterday’s cabinet meeting, Waltz praised Trump for his leadership as he hit 100 days in office.

But even that public display of fealty towards the president wasn’t enough to keep the axe from falling on his brief tenure atop the National Security Council.

When the majority of Trump’s cabinet reconvened Wednesday afternoon for an event to highlight business investment in the United States during the first 100 days of the president’s term, neither Waltz nor Wong were present despite there being reserved seats clearly marked with their names.