AceShowbiz - Taylor Swift, Jennifer Lopez, Celine Dion, and Sam Smith have answered Lady GaGa's call to join the line-up of stars for the "One World: Together at Home" concert extravaganza.

GaGa is curating Saturday's April 18, 2020 two-hour global TV special, arranged in partnership with officials from Global Citizen and the World Health Organisation, and had already secured remote appearances by Paul McCartney, Elton John, Chris Martin, Lizzo, Billie Eilish, John Legend, Kacey Musgraves, and Keith Urban among many others.

Now she has added Swift, Lopez, Dion, and Smith to the bill, alongside Alicia Keys, Usher, Pharrell Williams, and pop couple Shawn Mendes and Camila Cabello.

Also making cameos during the broadcast will be Oprah Winfrey, Ellen DeGeneres, Matthew McConaughey, Victoria Beckham, Lupita Nyong'o, LL Cool J, Amy Poehler, and Awkwafina.

"One World: Together at Home", co-hosted by comedians Stephen Colbert, Jimmy Kimmel, and Jimmy Fallon, will air simultaneously across the main U.S. TV networks from 8 P.M. EST, and be livestreamed on various digital platforms, as well as the Global Citizen Instagram and Facebook pages.

Global Citizen bosses are also putting on a six-hour preshow streaming event from 2 P.M. EST on Saturday, with artists like John Legend, Jennifer Hudson, Sheryl Crow, Lady Antebellum, Charlie Puth, Hozier, Michael Buble, Annie Lennox, Common, The Killers, Luis Fonsi, Adam Lambert, and new mum Maren Morris set to join in from isolation.

Others participating in the lead up to the main gig include Samuel L. Jackson, Sarah Jessica Parker, Liam Payne, Niall Horan, Don Cheadle, Rita Ora, Ellie Goulding, Ke$ha, Heidi Klum, Billy Ray Cyrus, James McAvoy, Jessie J, and Becky G.

Although GaGa has already helped to raise over $35 million for coronavirus relief efforts behind the scenes, she recently made it clear the "One World: Together at Home" main show is not designed to be a telethon.

Instead, she wants viewers watching in isolation to simply enjoy the performances, and "celebrate the heroic efforts of community health workers, and to support the World Health Organization in the global fight to end COVID-19."