Originally recorded in 1977 by Bob Marley And The Wailers, the new version of One Love features Marley’s daughter Cedella, son Stephen and grandson Skip.
It also features musicians from conflict zones and children living in vulnerable communities.
Tuff Gong International, the label and recording studio founded by Marley in the 1970s, and global record company Amplified Music, will release the record on July 17.
Proceeds from the song will go to Reimagine, Unicef’s global campaign to prevent the Covid-19 pandemic from becoming a lasting crisis for children.
Marley, who died in 1981 aged 36, had 11 children, many of whom have become successful musicians in their own right.
"Over 40 years ago, my father wrote One Love about unity, peace and universal love during a time when there was much trouble in the world," Cedella said.
"Even in a time when we aren’t able to get together, his message remains true today, we can get through this global crisis if we come together through one love and one heart."
Money raised will help Reimagine provide soap, masks, gloves, hygiene kits, protective equipment and information to children and families, as well as support recovery efforts and healthcare systems.
Jewellery brand Pandora, a Unicef global partner, is matching every US dollar donated by the public, up to one million US dollars, while social media network TikTok will host a launch event featuring a challenge as the song debuts online.
Unicef executive director Henrietta Fore said: "One Love speaks directly to one key truth about this pandemic: our best hope to defeat Covid-19 and to reimagine a more equal, less discriminatory world for children is through global solidarity and cooperation.
"We are delighted that the Marley family along with Pandora have lent their generous support, creativity and love to help the most vulnerable children."