Incoming White House Chief of Staff John Kelly plans to bring in one of his deputies from the Department of Homeland Security when he begins his new job Monday.

Kirstjen Nielsen, who has served as chief of staff under Kelly at DHS, will follow her boss to the White House, a Trump administration official told Fox News.

Nielsen will be White House deputy chief of staff, the source said.

"She’ll be the one person Kelly brings with him,” an administration official told Politico.

Kelly was named Friday to replace Reince Priebus as White House chief of staff. Priebus, a former chairman of the Republican National Committee, told reporters Friday that he had officially resigned a day earlier.

With Kelly leaving DHS, Washington has been crackling with speculation about who President Trump might pick to head the nation’s key security agency.

Candidates being mentioned, according to Politico, include Thomas Homan, acting director of U.S. Immigration and Customs Enforcement, Kansas Secretary of State Kris Kobach, an outspoken opponent of illegal immigration, and U.S. Rep. Michael McCaul, R-Texas, chairman of the House Homeland Security Committee.

Some have also raised the idea that Attorney General Jeff Sessions could move to DHS, Fox News reported.

According to the Hill, Nielsen was most recently president of Sunesis Consulting and served as a senior fellow and member of the Resilience Task Force at the George Washington University’s Center for Cyber and Homeland Security.

She previously worked in the White House under former President George W. Bush, where she was a special assistant to the president for prevention, preparedness, and response on the White House Homeland Security Council.

The most recent White House deputy chief of staff was Katie Walsh, who left the position in March to take a job with the non-profit America First Policies, the Hill reported.

Fox News' Jake Gibson contributed reporting to this story.