Yes, this is Stardoll. But, it can't be! Well, I don't to explain why it's not. These dolls were on the 'New Free' today (8th April).
I typed in 'diva girls games' on Google, to see if I could find this game, but found something else:
So Stardoll must've teamed together with 'Diva Girls' to get more members or, money. It's a bit of a sad idea, since most Stardoll members who have visited the Diva Girls doll on Stardoll haven't heard of them and don't have the faintest idea what and who they are. Also, most of the active Stardoll members are aged between 10-16 and I doubt they're going to play with cartoon things like 'Diva Girls'.