Ahh, Uta no Prince-sama is one title that I've never watched or even know about its character. I just know it is about singers and a lot of bishies! XD (should really try one day)
Kira looks quite similar with Ivan at first glance alright but has a longer and slightly messier hair... which is more young looking. The artist actually draws more similar characters like Kira's hair style, but I specifically sketched and requested Ivan to have a cleaner line at the back of the head and kinda spike out towards the front.