Donald Trump's presidential inauguration is scheduled to begin at noon ET. According to the U.S. Constitution's 20th Amendment, each presidential inauguration should take place Jan. 20, unless that date falls on a Sunday. Then, the president takes the oath of office in private Jan. 20, and the public event is moved to Jan. 21.

The former first lady will not attend the event but former Presidents Obama, Clinton and Bush are expected to be there.

The planned absence Monday follows another notable absence last week at the state funeral of former president Jimmy Carter.