Peter Andre has shown his support for the Stand Up to Cancer campaign.
The father-of-three is amongst many celebrities backing the charity's plea to get people across the UK involved in raising money to help fight cancer.
Melanie C and Dr Christian Jessen have joined the Mysterious Girl singer in tweeting pictures of themselves posing with the Stand Up bum-badge.
They are trying to encourage the country to stop sitting on their bums on Friday and join the nation in standing up to help beat cancer sooner.
The campaign suggests that people get sponsored to stand in weird and wonderful way. From standing rather than sitting for the entire day in the office, to pinball marathons and standing in unusual places, people will be pushing back their chairs, stretching their legs and Standing Up To Cancer.