The Duke of Cambridge and his younger brother will mark the 12th anniversary of the September 11 attacks on the World Trade Centre and Pentagon by joining traders in London's Docklands to make big deals over the phone.
American global financial services company, BGC Partners, lost 658 employees on 9/11 and has hosted an annual fundraising event in their memory since 2005.
Overall, they have raised £56 million for charity.
Organisers are hoping this year will be no exception - all money generated will be donated to good causes, including SkillForce, of which William is patron, and WellChild, of which Harry is patron.
More top news
Find out why the camp is being cleared now, where the refugees are being taken and how many unaccompanied children could head to the UK.
Syrian refugee children have been making clothes for British shoppers, it has been claimed.
A judgement is due on Monday on a Christian bakery’s appeal against a ruling that found them guilty of discrimination against a gay man.