Puma are attracting NEW customer because of Rihanna
What's so hard to understand?

Whether it's a partnership, she co-founded it WITH Puma...the consumers don't care
They see "Rihanna" "Fenty" "Puma" and buy, the same way they see "Beyonce" "Ivy Park" and "Topshop" and buy
Consmers don't care about the particulars of a contract