The American disco legend told of her delight after a video of Sergeant Jon Harris’ performance on the microphone went viral.
The Police Scotland officer and his colleagues had been called to deal with an alleged assault at the Waterloo Bar in Glasgow city centre on Wednesday night.
After interviewing people in the gay bar and studying CCTV tapes, Sgt Harris was persuaded to perform on stage in full uniform by the karaoke compere.
He danced and pointed his finger as he sang the disco hit while thrilled punters and colleagues filmed the action on their camera phones.
Gaynor, 66, took to Twitter and Facebook to share a link to the video and congratulated Sgt Harris for his efforts.
She said: “I love this! Sergeant Jon Harris performed a karaoke version of my classic hit song I Will Survive to help smooth tensions in Glasgow pub, the Waterloo Bar, after he and his fellow policemen were called in to take care of a brawl.”
Sgt Harris’ singing skills have also been praised by Calum Steele, general secretary of the Scottish Police Federation, who said he would try to recruit him for the police choir.
He said: “This is what community policing should be about - take a bow John and don’t forget the police choir are always recruiting.
“Top class example of policing being at the heart of our communities.”
At the end of the song Sgt Harris took a bow and got a standing ovation before going back to his duties.
After the performance karaoke host Katie Boyle posted on Facebook: “So I managed to get Sergeant Jon to sing in the Waterloo Bar today after a wee incident.
“It was an accomplishment that I got him up to do it. He was brilliant and just goes to show not all bad can be said about Police Scotland.”
After the video went viral, Sgt Harris’ boss Chief Inspector Mark Sutherland, area commander for Glasgow City Centre, said: “Around 7.10pm on Wednesday evening officers were called following an alleged assault within the Waterloo Bar on Argyle Street in Glasgow city centre.
“A full and thorough investigation led to the arrest of a 23-year-old male.
“Once the enquiry had concluded and the victim’s safety ensured, Sgt Jon Harris from our city centre Community Policing Team was encouraged to participate in karaoke ongoing in the pub.
“Sgt Jon took to the stage which helped to defuse any simmering tensions in the pub.
“I was pleased to see that once the incident had been professionally concluded, my officers were able to share a lighter moment with those who remained in the pub.”