Justin Trudeau makes formal appearance in Davos with Katy Perry  Toronto StarKaty Perry joins Trudeau in Davos to support former PM’s speech on value of ‘soft power’  CBCJustin Trudeau and Katy Perry attend the World Economic Forum in Davos  The Globe and MailIn Davos, Justin Trudeau argues for more of Canada’s ‘soft power’ as Katy Perry watches  National PostJustin Trudeau talks Canada’s ‘soft power’ in Davos as Katy Perry looks on  Global News