Mark Wahlberg has some words of wisdom for Justin Bieber! The Hollywood hunk sat down for a live web chat with U.K. newspaper The Sun and gave the Biebs a few quick tips on having better behavior. "Justin, are you listening? Don't be so naughty, yeah? Be a nice boy, pull your trousers up, make your mum proud, yeah? Stop smoking all that weed, you little bastard," he said jokingly (in a British accent, to boot).