Ariana Grande belts it out during Stand Up to Cancer on Friday evening (September 5) in Hollywood.

The 21-year-old singer performed her new song “My Everything” in honor of her grandfather who passed away from cancer.

PHOTOS: Check out the latest pics of Ariana Grande

“supporting a cause that is near & dear to my heart. tonight I’m singing for grandps! i miss u #StandUpToCancer @su2c,” Ariana tweeted before hitting the stage.

After the event, she tweeted: “sobbed my eyes out as soon as I got back. idk how he was just here & now he’s not & I’m singing a song in his honor. sucks a lot #f–kcancer.”