Singer Susan Boyle has revealed she is giving up sweets for the next 40 days as she backed a charity's Lent fundraising appeal.

The Britain's Got Talent star joined X Factor finalist Nicholas McDonald and broadcaster Kaye Adams in Glasgow to launch the Scottish Catholic International Aid Fund (Sciaf) Wee Box appeal.

Those taking part are urged to give up a favourite treat like coffee or chocolate for the 40 days of Lent, put the money saved in a Wee Box and then give it to Sciaf.

This year's appeal tells the story of the charity's work with women farmers in Africa, and every pound received before May 17 will be doubled by the UK Government.

The charity hopes to surpass the £800,000 raised by the Wee Box initiative last year.

Boyle said she will find it "very hard" to give up the treats for 40 days, and revealed that her favourite sweets are "cop cops" - small black sweets covered in sugar which she admitted may not still be available nowadays.

She said: "For many people, life is so tough that they dream of just having enough food to eat, being able to clothe their children and send them to school. I've been supporting Sciaf all of my life because I know that they help the poorest of the poor to have food and support themselves.

"This year, every donation given to the Wee Box appeal is being doubled by the UK Government, so everyone's help will go twice as far. I would encourage everyone to pull the stops out and really help Sciaf in every way you can."

McDonald, 18, is giving up the crisps he eats nearly every day.

He said: "So many people in poor countries still don't have enough food to eat. That's why I'm supporting Sciaf's Wee Box Lent appeal.

"I know the money they raise will help poor farmers in Africa to have a better life. I'm going to be giving up crisps and doubling my donation from the money I save. Please join in and help Sciaf change more lives."

Adams is giving up cheesy oatcakes.

Other high-profile Scots backing the campaign include adventurer Mark Beaumont, Premier League star and Scotland midfielder Darren Fletcher, Deacon Blue's Ricky Ross and long-time supporter Ally McCoist.

Sciaf director Alistair Dutton said: "We're incredibly grateful to everyone for supporting our Lent appeal. Whether it's giving a donation, putting on an event, or filling a Wee Box with small change, every penny will be doubled.

"That means that we can help many more people to free themselves from hunger and poverty."