Oprah Winfrey, Julia Roberts and former US President George W Bush will be among 200 participants in a 24-hour livestream raising money for the coronavirus relief effort.
The Call to Unite event will start on Friday evening and feature performances and conversations about overcoming the challenges of the coronavirus pandemic.
Quincy Jones, Jennifer Garner, Common, Maria Shriver, Questlove, Yo-Yo Ma, Eva Longoria, Naomi Campbell and Alanis Morissette are expected to participate in the event.
Event organisers hope participants can help inspire people to “emerge from this crisis better than when it began”.
Each participant will answer calls in their own way, whether through performing a song, sharing a story or offering a prayer.
The event will be livestreamed at unite.us and on Facebook, YouTube, Twitter, Twitch, LinkedIn and SiriusXM Stars.