Former "The Voice" star Grimmie was shot dead at a concert venue on June 10. She was 22.
Puth, 24, who originally recorded the song with Wiz Khalifa as a tribute to actor Paul Walker, performed a stripped down version of the number in memory of Grimmie, reported Female First.
"I was reading the news last night and heard that my good friend Christina Grimmie was killed, and I want to dedicate this song to her tonight. I've been upset about this all day, mainly because I just never got to say what I wanted to say to her, and I feel like this song perfectly captures that," Puth said.