Taguchi Junnosuke (ex-KAT-TUN) took a picture of the Tohoshinki Begin Again album release ad up at Shibuya’s Hachiko exit, and posted welcoming them back ^^.
Both seem to be friends. For example, back in 2013 on Kings Brunch, Changmin revealed that when Junnosuke came to Korea, they had barbeque together.
TVXQ! Express 