American singer Katy Perry and former Canadian Prime Minister Justin Trudeau have hard-launched their relationship on social media, laying to rest months of dating rumors. Perry, a 13-time Grammy nominee, posted on Saturday a video on Instagram that showed her eating sushi in Tokyo as Trudeau, with his arm behind her, looked on with an amorous gaze. “Tokyo times on tour and more,” Perry wrote in the caption of a carousel that included the video and also a selfie with Trudeau. The pop star was performing last week in Saitama, about 15 miles north of Tokyo, as part of her...