Daniel Wakeford of Channel 4's The Undateables will be in the Churchill Square, Brighton, to support Cancer Research UK.
The charity is holding a pop-up stall on the lower ground floor of the shopping centre ahead of World Cancer Day, which is on Monday (February 4).
Daniel, 31, from Brighton, volunteers at the charity's shop on Western Road and is expected to meet visitors from 2.30pm to 4pm.
They will also be able to talk to Cancer Research UK-funded researchers Dr Aya Abdalla and Marta Falcinelli from The University of Brighton, make a donation, sign up for charity events and buy World Cancer Day unity bands.
The pop-up stall will be open from 9am to 7pm and will officially be opened by Sheila Nutley, from Sompting, at 11am.
Sheila, 65, was successfully treated for breast cancer but her mother, mother-in-law, brother and friends have died of cancer. She will be available to talk to visitors about her personal experience and how she has helped the charity by sharing her story.
World Cancer Day is held to raise awareness of cancer and to promote its prevention, detection and treatment.
Cancer Research UK says that it spent £1million in Brighton alone on scientific and clinical research.