( CNN ) -- Most people need encouragement to remove their clothing . For Justin Bieber , boos from the crowd will do just fine . The 20-year-old singer stripped down to his skivvies at 2014 's `` Fashion Rocks '' event on Tuesday night in Brooklyn , where he was greeted with a negative reaction from some in the New York audience . As Bieber took the stage with model Lara Stone to introduce singer Rita Ora , there were some noticeable jeers mixed in with cheers . The singer seemed unfazed by those who were n't pleased with his appearance at the show , turning to Stone and telling her that he does n't `` feel comfortable unless I 'm in my Calvins . '' `` Calvins '' as in his Calvin Klein underwear , which he proudly showed off to the increasingly enthusiastic crowd . `` Grandma always said kill 'em with kindness , '' Bieber tweeted . `` And then strip on live national tv . Lol . '' According to Bieber 's Instagram , his striptease was impromptu . `` Just stripped on national television hahahaha it was n't planned lmao , '' he shared with his fans . If nothing else , it seems Stone approved . `` Thanks for that @ JustinBieber , '' the Dutch model posted to her own Instagram account .
Justin Bieber stripped on stage at `` Fashion Rocks '' The singer said he 'd feel more comfortable in his `` Calvins '' He later said the strip show was an impromptu moment .