The Duke of Cambridge has launched a new campaign to help stop people drowning in rivers.
William will travel by boat down the River Thames on Tuesday before launching a new drowning prevention strategy from Tower Bridge.
More than 30 people die on the Thames each year, with over 700 life-threatening incidents taking place.
William himself was called out to suicide incidents while working as an air ambulance pilot.
The strategy will address the risk of drowning through accidents as well as suicide.
It has been designed by the Port of London Authority, the Metropolitan Police, London Fire Brigade, Royal National Lifeboat Institution, London Ambulance Service and the Maritime & Coastguard Agency.
Agencies working across the entire stretch of the Thames are involved.
William will be joined at the launch by Jonny Benjamin, who was saved by a passer-by who stopped him from attempting suicide from Waterloo Bridge in 2008.
Neil Laybourn, the man who saved his life, will also attend, alongside suicide prevention minister Jackie Doyle-Price.
Mr Benjamin and Mr Laybourn met the Duke and Duchess of Cambridge in 2016.