Sailor Moon - Sailor Uranus x Sailor Neptune (Uranep / Harumichi) - Eternal Eternity

Hello! I've been listening to eternal eternity a lot lately, so I thought I'd doodle some more Haruka x Michiru art.
This one took me 3 hours, because I tried my best to make it look as much like the original picture as possible. I think the original picture is really beautiful, and I honestly couldn't be happier with how this turned out. ;w;
I seem to have a bit of an obsession with Sailor Moon again, haha. 0w0;
I really haven't been obsessed with this series since I was 9, though! xD
Anyway, I have a new cover coming up VERY soon!
I've been waiting to save it for February, so I'm pretty excited!
Hint!
It's a VOCALOID song, and it's probably the most popular duet song ever.
Still don't know?
Here's your last hint~
One of the singers is Miku, while the other singer is a Cryptonloid. (ex: KAITO, MEIKO, Rin, Len & Luka are all Cryptonloids)
Can you guess~?