Seo In Gook, the winner of 'Superstar K' season 1, took a friendly photo with his industry senior, IU. Seo uploaded the photo onto his Twitter on March 24th and wrote, "IU sunbae! Thank you for cheering for me~" The two first met when they performed IU's 'Nagging' together on KBS's 'Music Bank' last year, and reunited�at a clothing brand photoshoot two months ago. Netizens commented on how the two looked like siblings in the photo: "They look like brother and sister",�"Two cuties," and "IU's his senior?" Meanwhile, Seo in Gook, who revealed a sexy fetish concept for his upcoming album, will release his album on March 31st. Source: Newsen via Nate Photo: Seo In Gook's Twitter