The pianist and singer will play on top of the Shelter homelessness charity HQ in Old Street, London, on Tuesday, May 21.
The lunchtime show will also be streamed and fans can make requests on Twitter, the day after he releases new album Momentum.
Shelter chief executive Campbell Robb said: "This is the first time we've ever had someone perform live at our offices, let alone on our roof.
"It's great to have Jamie's support and we're really looking forward to hearing the new album."
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