Zayn Malik`s dramatic weight loss

Los Angeles: The pressure of being an international pop star is apparently taking a toll on One Direction singer Zayn Malik who seems to have lost a lot of weight in recent months. The 20-year-old British singer is losing weight because of stress and his busy schedule, the Us magazine reported. "He`s lost a lot of weight. He started to eat healthy a while ago and working out to get in shape as he had never trained before. He wanted some definition," a source said. "He`s always been the slimmest of the band members, naturally but I think he`s running around a lot, getting stressed, and not putting health first," the source added. Malik along with bandmates Harry Styles, Liam Payne, Niall Horan, and Louis Tomlinson -- has been working nonstop on One Direction`s 2013 US `Take Me Home` tour, which kicked off Thursday, June 13, at Fort Lauderdale`s BB&T Center. The group is expected to perform more than 35 shows in the next three months in the US. They`re also busy shooting their new movie `This Is Us` due later this summer. PTI