Tonight Show host Jimmy Fallon was the surprise commencement speaker at the Florida high school where 17 people were killed in a shooting rampage.
According to social media posts, Fallon told the 784 members of the Marjory Stoneman Douglas High class of 2018 to persevere in the face of difficulty and thanked them for their bravery and activism.
The ceremony on Sunday honoured four seniors killed in the February 14 attack.
Diplomas were presented to the families of Nicholas Dworet, Joaquin Oliver, Meadow Pollack and Carmen Schentrup.
Nikolas Cruz, 19, has been charged in relation to the shooting.
His lawyers have said he will plead guilty in exchange for a sentence of life without parole.
Prosecutors are seeking the death penalty.