"Come Thou Fount of Every Blessing", performed by Marcus Mumford in December 2020 for the Alzheimer's Society Christmas Caroling livestream.
This song is a hymn from the 17th or 18th century. There is also a video of Marcus's band playing it but this is a little higher quality.
This looks like it was filmed in his home and he's not got a mic attached to him, so the audio is medium quality.