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
Rain across central Britain with longer, intense downpours with thunder in places this evening. A lucky few will stay sunny and dry.
Planning on going to the London Marathon tomorrow? Read our handy guide first!
Labour plans to cap above-inflation rent rises over a three-year period, if they win the General Election.