The Washington as imagined in “House of Cards” requires some suspension of disbelief — but at least one scene this season will mirror real life.

Fans who stayed home Friday to get an early start bingeing on the addictive series may have noticed a rather convincing performance by a character playing a lawyer arguing before the Supreme Court.

The actor wasn’t really acting.

The man in the scene is Neal Katyal, the former acting U.S. solicitor general who filled in for Elena Kagan when she was nominated to the highest court, and who has argued 24 cases before the real Supreme Court. In the fourth episode, he’s up against actress Elizabeth Marvel, who plays the Underwood administration’s solicitor general, in oral arguments for a case about (small spoiler!) drone strikes.

Katyal exchanged e-mails with us Friday afternoon to discuss his experience playing, well, a version of himself on the show. Turns out that the man who “Above the Law” once described as “The Paris Hilton of the Legal Elite?” — after all the press he received when he successfully argued against the government in the 2006 Hamdan v. Rumsfeld dealing with Guantanamo detainees and military trials — was a natural.

Originally, Katyal was just called upon as a consultant, to chat with the writers about his experiences as solicitor general and before the Supreme Court. He took them to an oral argument, and introduced them to his legal team.

“The writers cared deeply about getting it right — even on the small details of oral argument at the court,” he said. “They knew they would at times have to depart from reality, but they always wanted to know what reality was so they could gauge what to do.”

Katyal was on a rare summer vacation in Europe with his family when he was contacted by show creator Beau Willimon about appearing in the Supreme Court scene as opposing counsel to the solicitor general — which would film eight hours after he landed. First thing? He called his barber back in Washington to squeeze in a haircut before his big debut.

Katyal was nervous when he walked on the set, but the realistic replica of the court — down to the podium (he said he wanted to buy it to use for practice sessions) — put him at ease.

“Because the fake court felt so much like the real one, my fear evaporated really quickly and it felt like any of my 24 real arguments,” he said.

He felt so confident in his performance that he was shocked to learn that in show business, the five-minute segment he’s in took dozens of takes and two days to shoot to account for multiple camera angles and other TV quirks.

He wouldn’t tell us any more about the plot or what other actors he interacted with except that Marvel was “completely absorbing” in her role as solicitor general. He, like most Washingtonians, plans to watch this weekend — after he takes his son skiing.

He doesn’t anticipate any future acting gigs. Though the extras on set were quite impressed with his bravura performance.

“So many of them came up to me during the breaks, asking how I learned how to act, which acting school I attended, what other films I had been in, and saying how realistic they thought I was in performing the role,” he said. (Emmy for Outstanding Guest Actor?)

But does he win his 25th case? Only 13 hours of binge-watching will tell.