Pauline McLeish, 46, from Wishaw will face her fears by swimming across Loch Lomond to help sick children in the West of Scotland.
Any cash raised will be put towards outings and an annual Christmas party for ill youngsters organised by charity champion Les Hoey.
Despite not being a strong swimmer, mum-of-two Pauline is determined to complete the mile-long challenge with her friend Karen Brown,
The pair have been training several times at the loch in preparation for Saturday's swim.
Pauline said: "We've tried swimming at different parts of the loch, trying out different currents and areas to prepare us. It'll be interesting to say the least.
"I think the fastest is 20 minutes, and the longest is more than an hour, so if I can finish before that I'll be happy."
Pauline's youngest son Ben, 11, spent a lot of time in Yorkhill hospital when he was born, something which influenced her decision to get involved with Les's charity.
Ben and her older son Ryan, 15, will be watching by the sidelines as she takes on the gruelling challenge.
Les, from Wishaw, was given an MBE last year for his mammoth fundraising efforts.
He said: "I think it's really fantastic that Pauline is doing the swim.
"It will be harder than she thinks but she's been doing some training too, so she'll do well."
To sponsor Pauline, visit www.gofundme.com/a5q70w