President-elect Donald Trump has offered Republican Rep. Elise Stefanik the job as US ambassador to the United Nations, two sources familiar told CNN on Sunday.

The New York congresswoman, the fourth-ranking House Republican, has been a strong ally of the president-elect and a major fundraiser for the GOP.

CNN has reached out to Stefanik for comment.

Stefanik, the House Republican Conference chair, has for years been one of Trump’s staunchest supporters in Congress. Her aggressive performance during his 2019 impeachment hearings made her a “Republican star,” as Trump himself said at the time. And again she stepped up for Trump after his 2020 defeat, when she objected to certifying President Joe Biden’s win in the House and promoted Trump’s false claims about election fraud.

But she wasn’t always Trump’s biggest fan: The New York Republican, who was the youngest woman ever elected to Congress at the time of her first win in 2014, voted against one of his signature legislative victories – his 2017 tax plan. A self-styled “independent voice” who had evinced a moderate persona, she’d previously won high praise from former House Speaker Paul Ryan, who wrote in Time magazine that Stefanik was a “builder – no easy feat in an age when so much of politics is about tearing people down.” She’d worked for Ryan during Mitt Romney’s 2012 campaign.

Once a Trump skeptic — and occasional outright critic — during his 2016 presidential campaign and into the early days of his presidency, she shifted from detractor to defender — a move she explained was due in part due to Trump’s popularity in her upstate New York district.

As Trump sought the 2024 Republican presidential nomination, she was among a handful of potential running mates, a role for which she openly jockeyed. She also told CNN earlier this year that she’s “proud to be a top surrogate” and “would proudly serve in a future Trump administration.”

Stefanik replaced then-Rep. Liz Cheney as GOP conference chair in May 2021 after the Wyoming Republican called out Trump’s election falsehoods. She is a member of the Armed Services Committee and the House Permanent Select Committee on Intelligence, among other committees.Stefanik made headlines last year with her campaign to oust college leaders who did not, as she and others saw it, adequately denounce antisemitism during a House hearing on the matter.

Trump said Saturday in a social media post that he “will not be inviting” back Nikki Haley, who served as UN ambassador under his first administration. Haley, the former governor of South Carolina, later ran a bitter primary campaign against Trump before dropping out and finally endorsing him months later.

This story has been updated with additional information.