She had been invited, with a phalanx of celebrities, to take part in a fundraiser at the City trading firm ICAP, three of whose staff turned up in Trump masks.
The brokering desks, where on other days multimillion pound deals are made, were transformed into party tables for the event, now in its 25th year.
Having stopped for a picture with the three Trumps – in reality IT engineers Tom Barry, Richard Tinworth and David Atherton – Camilla said with a smile: “I couldn’t resist it.”
During her hour on the brokering floor, she completed a series of deals which raised thousands for charities.
Among the other famous faces closing deals were the radio presenter Jeremy Vine, actor Bill Nighy, singer Ronan Keating and the actor Kelsey Grammer, known for the US sitcom Fraiser.
ICAP is an inter-dealer broker that matches buyers and sellers who want to trade in a range of products and Camilla was taken around the desks to chat to clients.
At the desk dealing with New Zealand dollar swaps, she picked up the phone to complete a $60m deal, with the help of Deborah Meaden, from the TV series Dragons’ Den.
Phil McMahon, a senior broker on the desk, said: “She was wonderful, she did very well
“It’s difficult to speak to someone you don’t know and make a deal.”