Williams and Barlow fell out during the Take That years Robbie Williams and Gary Barlow will perform live together later for the first time in 15 years.
The pair, who announced earlier this year they were working together again, will perform their new single Shame at a Help For Heroes concert in London.
“It’s great that people like Shame so much and we can’t wait to perform it live for the first time,” Barlow and Williams said.
Also in the line-up are Tom Jones, Alexandra Burke and Pixie Lott.
The concert, which takes place at Twickenham stadium and will be shown on BBC One, will also feature comic talent including Bruce Forsyth, Peter Kay, Michael McIntyre and Jack Dee.
Some 60,000 people are expected at the event – including 150 personnel injured in combat who will attend the show free of charge.
Proceeds will go to the Help For Heroes charity, which raises funds for wounded troops and their families.
Williams, who recently announced his return to Take That, said he was “honoured” to be asked to take part, and paid tribute to UK service personnel engaged in Afghanistan.
“Their dedication to our country is phenomenal and we are all so proud of them,” he said.
Katherine Jenkins, James Blunt, The Saturdays are among the other music acts.
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