Gerry Connolly, the USA representative from Virginia, also shared an image of Ms Pelosi and Ms Harris smiling and bumping elbows with each other.
There is one last bit of history to make, of course.
Vice President Kamala Harris, left, greets House Speaker Nancy Pelosi before President Biden's address. She said Biden was likely to begin the speech by turning around to face Pelosi and Harris and feeling proud - not just personally, 'but I also think proud for the country and proud for his party and I think he will clearly see the historic implications of this and the role that he played in making that happen'.
Biden recognized the historic moment at the start of his remarks, addressing "Madam Speaker, Madam Vice President", as the roughly 200-person chamber burst into applause.
"The word diplomacy generally suggests a relationship between government leaders, but I believe it has to be broader than that", she said.
"It's about time", Ms Pelosi said hours before the speech during an interview on MSNBC.
He acknowledged the moment by noting during his address to Congress after Ms Pelosi's election that he had the privilege of being the first president to open with the words "madam speaker".
She also sat at the rostrum for speeches by Presidents Barack Obama and Donald Trump.
Harris, the first woman and the first Black and Asian person to serve as vice president, sat to Biden's right. Others shared powerful images of the trio, saying, "The two most powerful women in the United States have Joe Biden's back", while someone else chimed in, "America, watch out for the shards".
In her role as president of the Senate, she joins Ms Pelosi to preside over the joint session of Congress.
The reporter who wrote a false story about books by Vice President Kamala Harris being handed out to children at a migrant shelter resigned on Tuesday, alleging she was forced to write the story and that it was her "breaking point".
The seating arrangement carried a symbolic meaning for the advancement of USA women in recent decades, since Harris and Pelosi stand first and second in the presidential line of succession, respectively.