Thousands of school kids are ditching their uniform in a bid to raise money for children's charity Unicef.
Around 4,500 schools across the UK are taking part in the Day for Change, where pupils pay to either wear their own clothes or to wear fancy dress.
All funds raised will help provide clean and safe water for children living in Ghana and Vietnam.
"We really want to help more children in Ghana have access to clean water," said pupil Tobie, from Peterborough.
Some of the kids taking part will be wearing clothes in the colours of Ghanian and Vietnamese flags.
The money will go to provide clean water for children in Ghana, where there is not enough safe water to drink.
But it will help children differently in Vietnam, where terrible flooding often puts people at risk and stop kids from going to school.