Billie Piper and Lily James joined a line-up of British celebrities on Thursday as they worked the phones and took part in the 21st BGC Group Charity Day in London, an annual event that donates all trading revenue and broker commissions to charitable causes.

The pair, longtime friends and frequent collaborators, appeared in good spirits on the trading floor and the red carpet. Piper, 42, wore a black faux-fur jacket over a "Choose Love" slogan T-shirt and a satin mini skirt with black boots. James, 36, chose a black jumper paired with grey pinstripe trousers. Other public figures who took part included Davina McCall, Amanda Holden and Holly Willoughby.

BGC Group said the event commemorates colleagues and brokers who died in the aftermath of the September 2001 attacks, and that 100% of the firm's revenues and broker commissions generated on the day are donated directly to participating charities. Since its inception, Charity Day has raised approximately £220 million globally, the company said.

Sean Windeatt, co-chief executive officer and chief operating officer of BGC Group, described the event as both "humbling and uplifting," and recounted the firm’s response after 9/11. "The first thing we had to do post-9/11 was look after the families of those we had lost," he said. He noted that the first BGC Charity Day took place in 2005 and that the initiative has continued to grow. Last year, the event raised more than $12 million globally.

This year's beneficiaries span grassroots and national organisations in the U.K. and international charities. Named recipients include HVH Arts, 20/20 Levels, The Pearl Fund, West Ham United Foundation, Battersea Cats and Dogs Home, The Mayor's Fund for London, Action Medical Research, Choose Love, Space for Giants and Help For Heroes, among others. BGC Group said it is supporting 60 charities in the U.K. and additional organisations worldwide.

Participants typically work alongside brokers and clients on the trading floor for a day of sponsored trading and fundraising. BGC Group and its brokers forgo commission on the day so that all proceeds can be directed to the chosen charities. Organisers said the event remains an opportunity for the City and business community to give back and for public figures to amplify support for a wide range of causes.

The 21st BGC Charity Day continued a pattern of celebrity involvement aimed at raising public awareness and funds for philanthropic work, with organisers and participants emphasising the event's direct financial support for both community-level and international relief efforts.