WASHINGTON — Special counsel Robert Mueller has materialized in Washington. On Monday night, he was spotted leaving Martin’s Tavern with actor and writer David McCallum, who plays “Ducky” on “NCIS.”

The strange pairing lit up Twitter, but the two men have been seen together in the past.

In January 2016, when McCallum held a DC book party for his first novel, “Once a Crooked Man,” Mueller was a guest.

Mueller is DC’s most in-demand date, with Democrats on the House Judiciary Committee trying to get the special counsel to testify before their panel. Senate Democrats want to hear from Mueller too, with Senate Judiciary Committee Chairman Lindsey Graham (R-SC) remaining open to it. President Trump, on the other hand, tweeted Sunday that he didn’t want Mueller to come before Congress. “No redos for the Dems!” the president declared.

A rep for McCallum has yet to return a request for comment.

Martin’s Tavern is the Georgetown restaurant where John F. Kennedy proposed to future first lady Jacqueline Bouvier.