Campbell, the platinum-selling singer-songwriter behind the number one single Colourblind, also sent campaigners a message of support. He tweeted: "Please save Bearsden Primary School - it's the heart of the community- can't imagine my childhood without it! #savebps"
The Save Bearsden Primary action group said it was delighted that the two famous former pupils had given their backing.
Spokeswoman Wendy McLaren hopes that locals will be encouraged to lodge their opposition to the closure in the council consultation scheduled for the new year.
Mrs McLaren said: "This is not just about the proposed closure of a school. We believe shutting Bearsden primary school, which has been at the heart of our tight-knit community for more than 100 years, will have a negative impact on our whole community."
East Dunbartonshire Council will hold a consultation on the plans between January 7 and February 4 next year.