There has been so much reshuffling within the Trump administration that political junkies can be forgiven for not knowing who has stuck around and who has moved on. The many comings and goings even prompted CNN's Don Lemon this week to touch on the notable "acting" positions before laughing off a "Game of Thrones"-style poster that overshadowed a cabinet meeting.

President Donald Trump in mid-December named Director of the Office of Management and Budget Mick Mulvaney as his acting White House chief of staff in place of John Kelly. Mulvaney, 51, had previously served as the acting director for the watchdog Consumer Financial Protection Bureau before being replaced on Dec. 6 by Kathy Kraninger.

Trump on Dec. 23 named Patrick Shanahan as the acting Secretary of Defense after abruptly replacing Jim Mattis two months before his resignation date.

Shanahan, 56, took over on Jan. 1. The former Boeing executive served as Mattis' deputy at the Pentagon.

There had been talk that former Virginia Sen. Jim Webb, a Democrat who once served as Secretary of the Navy, could take the position but Trump dispelled any notion Friday in a Twitter posting. 

In November, Trump announced on Twitter that Jeff Sessions' chief of staff, Matthew Whitaker, would become the acting attorney general. Whitaker, 49, drew controversy for not recusing himself from special counsel Robert Mueller's investigation into Russian interference in the 2016 presidential election.

The Senate Judiciary Committee will hold confirmation hearings on Jan. 15 and Jan. 16 for William Barr, Trump's pick for attorney general. Like Whitaker, Barr is considered a controversial choice, as he has been critical of Mueller's probe and supported the firing of FBI Director James Comey.

Barr, 68, served as the attorney general from 1991 to 1993 under President George H.W. Bush. 

After facing numerous legal and ethical violations, Scott Pruitt resigned as the Environmental Protection Agency administrator in July and was replaced by the EPA Deputy Administrator Andrew Wheeler. The 54-year-old Wheeler is slated to be nominated this month as the permanent chief of the EPA but faces scrutiny from Democrats, as he previously served as a coal lobbyist.

David Bernhardt, the acting interior secretary, is reportedly on Trump's short list to replace Ryan Zinke, who stepped down Wednesday amid allegations he violated ethics rules. Bernhardt, 49, who served as Zinke's deputy, is a former oil lobbyist and worked as an attorney for the Interior Department in the George W. Bush administration. 

Jonathan Cohen, the former Deputy Ambassador to the U.N., became the Acting Ambassador to the U.N. after Nikki Haley resigned on Dec. 31. Trump nominated Heather Nauert, 48, a former Fox News broadcaster and current State Department spokesperson, to become the permanent ambassador.

Bobby Ilich contributed to this report.