The Duke and Duchess of Sussex are to join famous names from the worlds of music, film and politics at a special concert in aid of the global vaccination effort.
The couple will serve as campaign chairs for Global Citizen's Vax Live event in Los Angeles next month, encouraging donations to Covax, which is working to provide vaccines for low and middle-income countries.
Hosted by Selena Gomez, the broadcast special on May 8 will feature musical performances by Jennifer Lopez, Pearl Jam's Eddie Vedder, Foo Fighters, J Balvin and HER.
Special guests, including Ben Affleck, Chrissy Teigen, David Letterman, Gayle King, Jimmy Kimmel and Sean Penn, will speak from around the world about vaccine equity.
US President Joe Biden, First Lady Jill Biden and Vice President Kamala Harris will also make special appearances through Global Citizen's partnership with the White House's We Can Do This initiative, which encourages measures including mask-wearing.
Appearances by French President Emmanuel Macron, Canadian Prime Minister Justin Trudeau and Croatian Prime Minister Andrej Plenkovic are also planned, organisers said.
Harry and Meghan said in a joint statement: "Over the past year, our world has experienced pain, loss, and struggle - together. Now we need to recover and heal - together.
"We can't leave anybody behind. We will all benefit, we will all be safer, when everyone, everywhere has equal access to the vaccine.
"We must pursue equitable vaccine distribution, and, in that, restore faith in our common humanity. This mission couldn't be more critical or important."
Harry recently returned to the UK to attend the funeral of his grandfather, the Duke of Edinburgh.
Meghan remained in the United States, having been advised not to fly while pregnant with their second child.
A trailer for Vax Live promised it will feature "big names and an even bigger message".
The event will be pre-recorded at SoFi Stadium in Los Angeles, California, and air on Saturday May 8 across networks including ABC, CBS, and iHeartMedia broadcast radio stations.