Pakistan, March 30 -- Zayn Malik's concert on Friday was cancelled on short notice. The former One Direction star, 32, called in sick hours ahead of his gig via an Instagram post, insisting that he tried pushing through but failed. "'I'm heartbroken to say that I won't be able to perform tonight in Mexico City," he began as he addressed the sudden cancellation on Friday. He continued, "I've been really sick since this morning and despite trying everything to push through, my body just isn't allowing it. I'm so sorry to let you down." "The love and energy I always feel from my fans means the world to me, and it hurts deeply to miss this moment with you. Thank you for your understanding and please know I'm sending all my love to each of you x...