President Trump sought Nikki Haley’s approval to call North Korean leader Kim Jong Un “Little Rocket Man” during his speech to the United Nations General Assembly, the former top diplomat wrote in her new book.

In his 2017 speech, Trump said “Rocket Man is on a suicide mission for himself and his regime,” shocking the room full of world leaders and the media.

Haley detailed how the moment happened in her book, With All Due Respect, which was published Tuesday. The former United Nations ambassador said Trump asked her to look over his speech a few days before he delivered it.

“What do you think of this?” he asked her, according to a copy obtained by the Washington Examiner. “What do you think of me calling Kim Jong Un ‘Little Rocket Man’ in the General Assembly?”

Haley said she initially advised against it because of the seriousness of the event.

“Remember when I said this was going to be like church?” Haley responded. “This is very serious crowd. That’s not something they would be used to hearing.”

“I tweeted it this morning and it’s killing on Twitter,” Trump said.

Haley said she recalled thinking that the president would do what he wanted, despite objections. “He was the president,” she wrote.

“It’s okay if you want to do it, just know that I don’t know what kind of reaction you’re going to get,” she told Trump.

Haley said she held her breath when Trump got the part about the North Korean nuclear threat.

“I watched the delegates look at each other. Some laughed. Some murmured. Others had to wait for the foreign language translation before they reacted. It created a kind of ripple effect in the room. Everyone was completely taken aback. But they also relaxed a little bit,” she wrote. “The media was scandalized, of course. … It was another case of Trump fascinating and disarming international leaders.”

[Also read: Trump says Kim Jong Un sent him a 'really beautiful letter']