Legendary singer, songwriter, and guitarist Paul Simon performed “Sound of Silence” at the 10th 9/11 Ground Zero memorial service.

Simon, wearing a 9/11 memorial cap, performed the song in front of bereaved family members and dignitaries.

Sunday’s performance isn’t the first time Simon moved people with his music over the tragedy of 9/11.  

On Sept. 21, 2001, just shortly after the 9/11 attacks, he sang “Bridge Over Troubled Water” on “America: A Tribute to Heroes,” a benefit concert for 9/11 victims and their families.

His 2006 Album “Surprise” was in large inspired by the 9/11 attacks and the U.S. military responses that followed.

“Paul Simon still has it. Incredibly moving performance. 9-11,” tweeted one person regarding his 9/11 “Sound of Silence” performance.

“This performance by Paul Simon today is so beautiful,” wrote another.

“You may think you know Sound of Silence. You don't know it like this,” wrote a third.