Click on photos below for full gallery of celebrities.
Star after star was spotted arriving at ICAP's London office to eagerly take part in the firm's annual charity day. The international dealer-broker company donates its total revenues made from the day to more than 41 organisations across the globe.
Dressed in a black and white, low cut blouse and matching black trousers, Cheryl looked confident as she manned the phones and closed lucrative business deals.
At one point the former X Factor judge struggled to hear from the commotion and buzz in the office, and pulled funny faces as she held her hand to her ear.
The Newcastle-born beauty was joined by Millie Mackintosh on the trading floor, who looked to be enjoying herself and highly entertained by some of the office workers who were sporting fancy dress.
"Made some new friends @lgfbuk @icapcharityday," tweeted Millie, alongside a photo of her and two employees dressed as gorillas.
The Duchess of Cornwall was also pictured getting into the spirit as she animatedly picked up phones and sealed deals alongside Barbara Windsor and Craig Revel Horwood.
The Strictly Come Dancing judge had Camilla in fits of laughter as he triumphantly raised two phones in the air after closing a deal.
Camilla at one point looked slightly overwhelmed as she held out her hands in despair and smiled sheepishly. The 66-year-old royal was later shown around the makeshift displays in the office, including the tiki-themed beach bar where she had a go on a surfing simulator game.
Other celebrities who took part in the charity day included Homeland star Damien Lewis, who answered phones next to male employees dressed as nuns, pop band JLS, actress Julie Walters and Westlife's Brian McFadden.
Since its launch in 1993, the ICAP charity day has raised more than £100million for over 1,400 charities.