There’s a new character about to take the stage in the impeachment drama. President Trump and Secretary of State Mike Pompeo may not like what he has to say.

Phil Reeker, the assistant secretary of State in the Bureau of Europe and Eurasian Affairs, is set to appear for questioning Saturday on Capitol Hill. Congressional aides say they’re unsure which members will show up to the weekend session but two individuals with knowledge of Reeker’s plans say the State official will likely unveil additional details about the efforts to push out former Ambassador Marie Yovanovitch, including who above him at the department knew about the campaign, and when. Reeker is also set to touch on what he knew of Ambassador to the European Union Gordon Sondland’s involvement with Rudy Giuliani and the effort to convince Ukraine to investigate Hunter Biden, sources say.

Reeker kicks off another long string of depositions in the impeachment inquiry that includes the highly-anticipated testimony of the first national security council witness—Senior Director for Europe and Russia Tim Morrison—as well as Charles Kupperman, former deputy assistant to the president for national security affairs.

Reeker is the sixth State Department official to testify in the inquiry, which has focused in part on how Pompeo and his staff learned of and handled a shadow effort by the president’s personal attorney to run U.S. foreign policy on Ukraine. His testimony is expected to deal another blow to a department where officials are now working overtime to try and restore confidence in the U.S. foreign policy system.

An attorney for Reeker did not respond to a request for comment. But those who have worked with Reeker in the past describe him as a straight shooter who is well-liked in the department.

“He is a career guy. He’s been at this a long time and he’s not about to give that all up to protect anyone,” one State Department official told The Daily Beast.

Since taking up his post in March, Reeker has spent a significant amount of time interacting with Sondland and dealing with Ukraine policy, according to officials with knowledge of his schedule. Reeker also holds a direct line to senior officials at the department including David Hale, the under secretary for political affairs, as well as Secretary Pompeo. During the effort to oust Yovanovitch, Reeker reportedly relayed concerns by George Kent, his deputy, about the campaign to Hale.

In his testimony earlier this week, William Taylor, the top diplomat in the country, said President Trump, in a phone call with Sondland, said Ukrainian President Volodymyr Zelensky had to “clear things up and do it in public” before the shipment of military aid to Ukraine. Individuals familiar with Reeker’s plans say the career diplomat is likely to confirm parts of Taylor’s testimony as it relates to Sondland and Yovanovitch.

“I have a feeling Phil will go in there Saturday and do exactly what Taylor said,” the State Department official said.

Even before he assumed his current role, Reeker occasionally worked with Sondland. Reeker, a career diplomat, previously served as the civilian deputy commander at the U.S. European Command in Stuttgart, Germany. In February he traveled to Odessa, Ukraine with Sondland, Kurt Volker, the former U.S. representative for Ukraine negotiations, Andrzej Sadoś, a Polish diplomat who serves as a permanent representative of Poland to the European Union, and Ana Birchall, the Romanian Minister of Justice.

In April, in the midst of the beginning of a campaign to remove Yovanovitch, Reeker attended a dinner hosted by Sondland in Brussels. The dinner was in honor of the EU Ambassador to the U.S. Stavros Lambrinidis.

Other U.S. officials in attendance included former White House Press Secretary Sarah Sanders, Energy Secretary Rick Perry, Commerce Secretary Wilbur Ross, U.S. Trade Rep. Robert Lighthizer, Larry Kudlow, top economic adviser to President Trump, Fiona Hill, Trump’s former top Russia adviser and Urlich Brechbuhl, the State Department’s counselor. Birchall also attended the dinner.

Birchall met with Attorney General Bill Barr in June in Romania and Barr subsequently invited the minister to Washington. In a recent interview with Fox News, Giuliani suggested he had information about the Bidens’ dealings in Romania, saying “I haven’t got to Romania. Wait til’ we get to Romania.”

Reeker inherited what State Department officials describe as a “beat-down” bureau in March, following the tenure of Wess Mitchell.

“Mitchell created a really uncomfortable dynamic for a lot of career people,” a former State Department official said. “He pushed forward a log of Trumpian views, like engaging with autocrats, that had some geopolitical wrapping around them. The bureau was run into the ground on the back of these ideas that are just kind of ... not tenable.”