Sometimes rock stars get out of hand onstage—sometimes they’ll smash instruments or swear or light stuff on fire. And sometimes they’ll curse at seven-year-old girls. Or maybe that’s just Pete Townshend. Either way, the guitarist has now issued an apology to the fan.

On February 19, the Who played a concert in Hamilton, Ontario. Seven-year-old Jenny Costello was sitting on her father’s shoulders waving a sign that said, “Smash your guitar, Pete!” Townshend saw the sign and was immediately set off.

“Go away with that sign please, just go away with it, just go away with it. Don’t bring your children…I want to tell you two words, but I can’t because you’ve got a child there,” he said into the microphone. He then mouthed the words “fuck you.”

Afterwards, Jenny’s father, Eric Costello, had a few choice words for the musician. “Nobody talks to my seven-year-old daughter like that,” Costello told the Toronto Sun. “I expect a 70-something-year-old man to respect the fact that there’s a seven-year-old girl standing in front of him…I’d like [Townshend] to know in some small way, he broke a little girl’s heart.”

Townshend wrote a personal letter of apology to the family. “Apologies and condolences from my side and very best wishes to you and your family,” he wrote. “I am most certainly not angry…I was not angry on stage either. I was in rock star mode, the big mouth,” he continued in the letter. “I could have handled it differently…[I hope we can] meet and be friends and put this behind us.” Townshend plans to meet with the family in April.