The chart-topper will fire the starting gun on a brand new contest which will be open to all singer-songwriters over the age of 17.
BBC Radio Scotland, which is launching the competition with a live event starring Capaldi in Glasgow next week, is asking entrants to submit short videos which must feature both an original composition and a cover version.
A 10-strong shortlist chosen by a panel of industry experts will be revealed in September, with four finalists then due to be selected via a public vote.
They will be mentored by musician and songwriter Davie Scott in the run-up to a final showdown hosted by Deacon Blue singer Ricky Ross on 26 September.
Ross said: "Great storytelling is at the heart of a great song. The lyric, the right chord change, the story and how that connects emotionally with us every day make a great song part of our lives.
"This award is a fantastic opportunity for aspiring singer/songwriters in Scotland."
Sharon Mair, executive producer at Radio Scotland, said: "As far as musical talent is concerned, Scotland has always punched well above its weight.
"BBC Radio Scotland has been at the forefront of developing musical talent in Scotland for the past 30 years.
"I'm so pleased we are launching this award, which will provide a great platform for new talent looking for opportunities in 2019."
BBC Radio Scotland already stages an annual competition to find the country's young traditional musician of the year.