As Obama, Clinton, and Hillary, entered the US Capitol rotunda in Washington, D.C., for Trump’s historic swearing-in ceremony on Monday, loud boos echoed from the crowd at the Capitol One Arena

Former President Barack Obama arrived at the U.S. Capitol on Monday for President-elect Trump’s inauguration ceremony without former First Lady Michelle Obama.

Michelle Obama was the only spouse absent at the funeral service at Washington National Cathedral, where her husband and Trump were seated next to each other and chatted and laughed like old friends despite the history of political animosity between the Democratic former president and the returning Republican.

WEST PALM BEACH, Fla. -- Former first lady Michelle Obama will skip the inauguration of President-elect Donald Trump, the second time in two weeks that she is not attending a gathering of former U.S. leaders and their spouses, but former Presidents Barack Obama, George W. Bush and Bill Clinton will be there.

Michelle Obama was the only spouse absent from the service last week at Washington National Cathedral, where her husband and Trump were seated next to each other and chatted and laughed like old friends despite the history of political animosity between the Democratic former president and the returning Republican.

A spokesperson for Pelosi, who attended Trump’s 2017 inauguration, did not provide an explanation for the move.

The two shook hands before Trump took his seat next to former President Barack Obama ... The row with Obama and Trump also includes George and Laura Bush and Bill and Hillary Clinton. Trump and Pence have not been seen together since leaving office ...

Former President Barack Obama was spotted at the inauguration of Donald Trump. See pictures of the former president here.

LIVE: Donald Trump is now the 47th President of the US. He was administered oath at the US Capitol Rotunda. Stay tuned for Donald Trump Inauguration LIVE Updates

Donald Trump, who overcame impeachments, criminal indictments and a pair of assassination attempts to win another term in the White House, was sworn in Monday as the 47th U.S. president, taking charge as Republicans claim unified control of Washington and set out to reshape the country’s institutions.

President-elect Donald Trump has selected opera tenor Christopher Macchio to perform the national anthem at his second inauguration.