Hillary Clinton will endorse Joe Biden’s presidential candidacy later on Tuesday, sources said.
Mrs Clinton, the former secretary of state and 2016 Democratic presidential nominee, is expected to announce her support in a virtual town hall meeting with Mr Biden later on Tuesday.
Mrs Clinton teased the announcement by tweeting a picture of her, Mr Biden and then President Barack Obama laughing in the Oval Office.
As the 2016 Democratic presidential nominee, Mrs Clinton made history by becoming the first woman to lead a major party’s ticket.
Her endorsement is the latest sign of the Democratic Party rallying around its nominee to challenge President Donald Trump.
Although she beat Mr Trump by three million votes in the 2016 popular vote, her opponent won comfortably in the all-important Electoral College by taking several key states, notably in the Rust Belt.