TV viewers are being given the chance to vote for the Scottish building they would most like to see restored.
The post-Reformation church is on the tip of the Black Isle
The entrants selected for BBC Two's Restoration Village programme are Cromarty East Church, Dennis Head Old Beacon, Orkney, and Greenlaw Town Hall.
Film star Tilda Swinton, who grew up in the Borders, is supporting the Greenlaw town hall bid while three River City actors are each backing a project.
Friday's winning entrant will go through to the final in September.
A total of 21 buildings across the UK have been entered into the competition.
One will be selected from each of seven areas for the final, which will also include the best runner-up.
The Heritage Lottery Fund has set aside £1.9m for the programme which will allow for both a main prize for the winner and a series of smaller planning grants up to £50,000 for other finalists.
Joyce Falconer, who plays Roisin in River City, is giving her backing to the Cromarty East Church on the Black Isle.
"For four centuries it has been at the heart of the cultural and spiritual life of the community in Cromarty and I fully support their bid to keep that heritage alive by teaching schoolchildren about traditional skills through the restoration process," she said.
Greenlaw Town Hall is a Grade A Greek Revival building
The Old Beacon in North Ronaldsay is currently unsafe and is described by the programme's presenter Griff Rhys Jones as housing "200 years of bird poo".
But the local people hope to secure its safety and install a spiral staircase to let people go to the top to see amazing views of the land and sea.
They also hope to restore the adjoining cottages.
The bid is being supported by Tony Kearney, who plays Scott in River City and is originally from Barra.
He said: "Dennis Head beacon is an iconic landmark - a symbol of the seafaring history of this country.
"As a fellow islander I'm right behind it 110% and it would be great to see its light shining in time for 2009 - the bicentenary of its de-commissioning when its beacon was replaced by a stone ball."
The lighthouse and its keepers' cottages need restoration
Libby McArthur, who plays Gina in the soap, is backing Greenlaw Town Hall, a Georgian building which sits at the heart of a Borders village of just 600 people.
"Where could you have your ceilidhs and dances if it wasn't for the town hall, and this is a real belter of a town hall - the town hall of town halls," she said.
Her fellow town hall supporter Tilda Swinton said: "The restoration of this beautiful and elegant building would be a vibrant reminder to all of us that making something living and civic and functional need not mean making it hideous and soulless.
"We deserve buildings that are good for the soul as well as practical for our lives."