KT Tunstall and Amy Macdonald will provide the entertainment later for around 10,000 people spending the night outdoors in a mass sleepout to raise millions for the homeless.
The singers will start the night in Aberdeen before being taken by helicopter to gigs in the other participating cities – Dundee, Glasgow and Edinburgh.
Organisers of Sleep in the Park hope to beat the £4 million raised by last year’s single event in Edinburgh, which had 8,000 participants.
The cash goes towards tackling homelessness through housing projects and employment programmes, and supporting those on the streets with shelters and hot food and drink.
KT Tunstall, who released her latest album, Wax, in October, tweeted: “So glad to be taking part in @SocialBite_ #SleepInThePark on Saturday to raise a ton of money and awareness to help Scotland’s homeless.”
Comedian Fred MacAulay is hosting the Edinburgh event, with a performance by Lulu and a bedtime story from Trainspotting author Irvine Welsh in West Princes Street Gardens.
Frightened Rabbit, whose lead singer Scott Hutchison died in May, will play at Kelvingrove Park in Glasgow.
Eddi Reader will headline Aberdeen’s show in the Duthie Park, while Kyle Falconer will top the bill in Dundee’s Slessor Gardens.
The event ends on Sunday at 6am.
Josh Littlejohn, co-founder of organiser Social Bite, said: “We were completely blown away by the thousands of people who joined this movement and supported Sleep in the Park last year.
“We want to build on this across the whole of Scotland.”