Rihanna -- Repping Puma Now ... Usain Bolt Rejoices

Rihanna just got a huge gig with Puma -- and aside from maybe Puma stockholders ... no one is more excited about this than the fastest man in the world.

First, RiRi's gig -- she's been named creative director of Puma ... and a company rep says she'll not only work on designs, but also serve as a brand ambassador. She celebrated her new job by posting pics in some Puma kicks.

Now, the good stuff -- Puma's other big spokesman is, of course, Usain Bolt ... and we know the Olympic sprinter's been jonesin' to hookup with Rihanna because he told TMZ Sports about his crush last year.

We're guessing Usain's on the phone to Puma brass right now with all kinds of new promo ideas.