The "Love Yourself" singer pleasantly surprised Beliebers Tuesday afternoon when he delivered a sneak peek at his campaign with Calvin Klein underwear. the 21-year-old wrote on Twitter "I flaunt in #mycalvins," This isn't the first time Justin has stripped down to his favorite underwear. In January 2015, the singer got some fans hot and bothered when he debuted his first undies ad alongside a shirtless drumming commercial.