Victoria Beckham thanked the audience member on the band's website after he handed the item in to security at London's 02 Arena last week.
She wrote: "Mel B lost her bracelet as it flew off in to the audience and we want to say a big thank you to David who picked it up and contacted our management company to tell us that he had it.
"We're really grateful to him for being so honest and we'll be meeting up with him before one of our concerts in January to thank him in person."
Posh also revealed that she is looking forward to the festive season, saying: "It will be great to spend time with David, the boys and my family. We are taking the boys to see Father Christmas and they are so excited!"
She recently had stage outfits worth thousands of pounds stolen at a Spice Girls concert.