Paul Simon performed his classic track The Sound of Silence at the funeral of a teacher who died in the school shooting in Connecticut on 14 December.
The 1966 song was understood to be a favourite of 27-year-old Victoria Soto, a first-grade teacher at Sandy Hook Elementary School.
The singer, a family friend, performed the song in front of some 400 mourners, at Soto's local church on Wednesday.
Twenty six people were killed by Adam Lanza in the mass shooting last week.
Among them were 20 children, all aged between 6 and 7.
Soto was killed while shielding her pupils from gunfire. She is understood to have hidden some of the children in a closet, ensuring they were safe, and then told the gunman that her class was in the gym.
Simon is believed to know the Soto family through his sister-in-law, who is a nurse like Victoria's mother. He received no introduction at the funeral and left without making any comment.
Soto grew up in Stratford, Connecticut and graduated from Eastern Connecticut State University. She was studying for a master's degree in special education.
"She lost her life doing what she loved," her cousin, Jim Wiltsie told ABC News.