The 26-year-old said he can't remember the last time he went out with Stewart, 22, and didn't get mobbed by fans, reported Daily Star.
"It's extremely rare to go out for a beer like a normal guy. I don't know why. Something about my face people just recognise really quickly. Kristen can go out and people don't notice. She can hide in crowds.
"I probably give myself away by walking around with a hoody and a hat and sunglasses, bent over and hiding my face. I probably look like a lunatic," he said.