Today, IVE was a guest on Music Station, one of Japan's most popular and prestigious music shows. And KAT-TUN (a popular Johnny's ENT. group) was on the show to promote their new single. We learned that Rei's mother is a KAT-TUN fan and Rei also likes their songs too. 
The way Kazuya repeats " Jiinjjaa?" 
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In case you were wondering about KAT-TUN, it's a Jpop/Jrock band affiliated with Johnny's Ent. They're debuted in 2006 with 6 members. Now there are only 3 members left. 
MVs of some of their songs,
GIMME LUV PV KAT-TUN_哔哩哔哩_bilibili
www.bilibili.com
LIPS PV KAT-TUN_哔哩哔哩_bilibili
www.bilibili.com
RESCUE PV KAT-TUN_哔哩哔哩_bilibili
www.bilibili.com
They are also one of the rare Jpop groups to perform in Korea and be a guest of Korean music shows. 
