Accountants are known for cutting their cloth accordingly but can they live off just £5?
Staff at Preston-based firm Rotherham Taylor Limited are taking part in the challenge.
Chief executive Michael Barton and director Rebecca Bradshaw join staff in attempting the challenge.
Rebecca said: “We chose the Foxton Centre as our charity of the year in recognition of the real difference it makes to people locally here in Preston.
“This is set to be a very tough challenge, but it is the daily reality for many of the people that the Foxton Centre works with.
“We hope to be able to raise a good sum for the Foxton Centre.”
Based in Navigation Way, Ashton-on-Ribble, the staff can only eat and drink a fivers worth from Sunday 26 March.
Read more: How homelessness in Preston is tackled could be changing
The team are hoping to raise £500 for The Foxton Centre, which provides help and assistance for the homeless in the city.
You can support the team on their Justgiving page.