A donor has pledged to match every pound raised for Dementia Jersey through this weekend's Jersey–France Challenge, up to a total of £20,000.
It's been made through the charity's Donor Advised Fund with Jersey Community Foundation, and means each donation by islanders will essentially double.
A £10 gift becomes £20, and a £50 gift becomes £100.
The Jersey-France swim challenge will begin at La Coupe Bay on Saturday, 8 August, where one team member will dive straight into the sea to start the swim relay.
The 14-mile swim will take teams of two to six people to the beach north of Carteret Marina, via the south of Les Ecrehous.
Nadine Jagger-Ferguson, Fundraising and Communications Coordinator at Dementia Jersey, said:
“It's so generous, and we are so grateful; being able to double the money raised makes a huge difference.
"Every pound raised helps us continue to do what we do for islanders with dementia and their families and carers.
"Fundraising like this really makes a difference in people's lives, so we'll be cheering them on, and wishing them a smooth crossing!"
You can donate here.

Haut Du Mont Trial: 'It could explode', jury hears 999 calls
Haut Du Mont Trial: Worker checking gas valves spent almost 'entire' time on his phone
Red Arrows still expected for Jersey Air Show
Haut Du Mont Trial: Gas works were 'sloppy, unsafe, and cut corners', allege prosecutors
26 Victoria Village homes get planning permission
Haut du Mont trial: Explosion 'an incident waiting to happen'
Jersey flights impacted by UK air traffic control issue
Engine fault sees private jet diverted to Guernsey Airport