Hillary Clinton set to endorse Joe Biden's presidential bid

U.S. Vice President Joe Biden (L) and former Secretary of State Hillary Clinton (R) attend a ceremony to unveil a portrait honoring retiring Senate Minority Leader Harry Reid (D-NV) on Capitol Hill in Washington, U.S. December 8, 2016.  REUTERS/Jonathan Ernst

NEW YORK, April 28 (Reuters) - Former presidential candidate Hillary Clinton will endorse the campaign of her fellow Democrat Joe Biden on Tuesday, according to a person familiar with her plans.

The endorsement, set to take place at a 3 p.m. briefing online, marks the latest in a series of high-profile Democrats lining up behind Biden ahead of what is expected to be a tight election contest against Republican President Donald Trump.