By Amber Goodhand - Radar News Editor
"I had this argument with Adele, which is probably the most ridiculous thing I've ever said," he told Canada's George Stroumboulopoulos Tonight.
"I was saying, 'You know, you can really just like reach for it,' and she was like, 'You do realize I am like the biggest-selling female artist ever?'"
Rob, 26, explains that's when he decided to get into it with her.
"And I just for some reason just decided to get into an argument with her," he said.
"I woke up the next day really regretting the whole thing."
"I've always been like this. I'm one of those people who is dying to go to the party and then when I get there I just hang out in the corner with the people I came with, not talking to anybody else anyway," he said.
"I have this fantasy that if I wasn't famous I'd be out meeting random people on the street but that's not true. Most of the time you try to avoid random people on the street whether you're famous or not."