The president-elect said he "didn't realize" one thing about the exchange at Jimmy Carter's funeral until he saw footage of it.

The former president and once-again-future president, who are historically something less than besties, chatted it up before the service began. (Michelle Obama was not in attendance.)

Trump is obviously no fan of Biden, but Obama and his veep also have a famously complex relationship, only made more so after Obama helped nudge Biden to quit the presidential race last summer. Surely Obama feels some frustration that Biden fumbled a possibly winnable race; maybe he couldn’t help spill to his sworn enemy?

Former first lady Michelle Obama didn't attend the state funeral for former President Jimmy Carter. Except for Michelle Obama, all of the living former presidents and their spouses were at the funeral Thursday.

The former first lady was notably absent from President Jimmy Carter's state funeral service, leading Barack Obama and Donald Trump to be seated next to one another

Former President Barack Obama attended Jimmy Carter’s state funeral on Thursday without his wife, Michelle Obama, although a spokeswoman for the former first lady said she sent her condolences to the Carter family.

Former first lady Michelle Obama did not attend President Jimmy Carter's funeral at the Washington National Cathedral — and social media took note.

Clinton, Bush, Obama, Trump — seated together at Carter's funeral in Washington. pic.twitter.com/7QrfyH0ha3 Barack Obama was seated next to Donald Trump, and the two were very conversational. They were truly yucking it up.

Donald Trump and Barack Obama sat next two each other and chatted during the funeral service for former President Jimmy Carter at Washington's National Cathedral. Trump engaged Obama for several minutes before the start of the funeral.