The annual event, which will take place at Rudding Park Hotel on Saturday 10 November, will have a spectacular Brazilian Carnival theme.
Ellis-Bextor, whose biggest hits include Murder on the Dance Floor and GrooveJet (If This Ain’t Love), is expected to keep the party going well into the night.
The singer said: “I’m excited to be performing at The Firecracker Ball, which everyone knows raises a significant amount of money for Barnardo’s every year.
“It’s a fantastic event and I feel privileged to have been asked. And as for this year’s Carnival theme, I’ll definitely make sure my performance ensures it lives up to it.”
Barnardo’s vice president and chair of the Firecracker Ball committee, Phil Taylor, said: “We’re thrilled to have Sophie joining us.
“I’m sure her presence, combined with the carnival theme and the magical way our team will bring it to life for our guests, will ensure this year will be our biggest and best ever.”
Visit www.thefirecrackerball.co.uk for information about the Firecracker Ball.