The reality star tweeted out an old picture of herself, sister Kendall Jenner and Grande at a concert together, writing, "Concerts are supposed to be a place where u can let loose & have fun. So scary to not feel safe in this world. @arianagrande I love you."
"I'm praying for everyone in Manchester," the 36-year-old mother of two added. "This is truly so senseless & heart breaking."
Kardashian West, who is a big fan of Grande's, brought her 3-year-old daughter, North, to the Los Angeles stop on the singer's Dangerous Woman tour at the end of March, where the three palled around backstage.