Now, in support of his girlfriend, Mac has cancelled his shows to be by Ari's side during the difficult time.
His performances were planned for Memorial Day Weekend, at the Sasquatch Festival in Washington, and the Soundset Festival in Minnesota, Billboard reports.
He tweeted the following:
"Soundset and Sasquatch, I will not be performing this weekend. Thank you for understanding. I'll be back. Love always."
Ariana sent out her official statement over the weekend, where she promised her fans that she will be back in Manchester to hold a benefit concert for the families' that have suffered.
She has called on her fellow celebrity friends to join her in concert.