I've punched one of the Arctic Monkeys, no idea which one as I didn't realise he was a member of the Artic Monkeys (which largely contributed to why I punched him). The short version is, he was a ****.
Slightly longer version. Out for a few pints with a bunch of people and one of the girls asks this scruffy looking guy if he'll take their picture and hands him her iPhone. It turns out, he is one of the Arctic Monkeys, so thinks she wants a photo with him. Upon realising that she doesn't know who he is and just wants him to take a picture of her with his friends, he throws a dive strop, smashes the phone on the ground, stamps on it, then sarcastically says "whoops". I punch him, I get thrown out by bouncers, all my friends kick off and get kicked out and I later find out he's apparently in the Arctic Monkeys. Luckily nothing came of it, but he was a prick.