Topless Irina Shayk joins Nigerian schoolgirl's safe return campaign on Twitter

London: Irina Shayk recently posted a topless picture of hers on Twitter whilst joining the social media campaign demanding Islamic terrorists should return hundreds of kidnapped Nigerian schoolgirls.Shayk, who is dating footballer Cristiano Ronaldo, was criticized by several Twitter users as she covered her modesty with the piece of a cardboard, which had "bring back our girls" written on it, the Mirror reported.The Sports Illustrated model joined the campaign after Angelina Jolie, Michelle Obama and Cara Delevingne became a part of it.