Director of the telecast says singer’s performance of “My Everything” was one of the night’s highlights

Stand Up to Cancer didn’t have one problem with Ariana Grande.

After reports surfaced Saturday morning that “The Way” singer was “a total nightmare” backstage, the show’s executive producer and director is speaking out to refute the accusations.

“The U.K. Daily Star‘s story on Ariana Grande is completely false,” Joel Gallen tells E! News exclusively. “Ariana was wonderful to work with, very gracious and a consummate professional to our team and everyone at the Stand Up to Cancer telecast.”

He added, “Her moving performance of ‘My Everything,’ which she sang in honor of her grandfather who passed away from cancer, was one of the most emotional moments of the night. We were honored to have her join us.”