Rihanna discovered her B**ch Better Have My Money music video co-star by trawling through Instagram.com.

The Rude Boy hitmaker stunned fans last week (ends05Jul15) when she unveiled the promo clip for her single, which depicts images of kidnap, drug-taking and weaponry as well as a shot of Rihanna completely drenched in blood after committing a brutal crime.

The video features famous faces, including Mads Mikkelsen, Eric Roberts and Rachel Roberts, but the singer plucked one of her co-stars, Sanam, from obscurity using the photosharing site.

Sanam, who uses only her first name, tells Vice.com, "I got a (direct message) from (Rihanna) on Instagram. She was like, 'Hey, I have this idea I want to run by you. I think you're so f**king rare. Let me know if you're interested.'... I was just freaking out, because Rihanna is messaging me on Instagram, telling me that she thinks I'm cool.

"Then I got another message from someone who works for the production company that made the video, and they were like, 'We want to put you in Rihanna's video!... At first, I was just like, This can't be real. This is really weird... At the end of the day, they were like, 'We just got the confirmation from Rih: We want to cast you, and we want to fly you out tomorrow.' And I flew down there the next day. She followed me on Instagram on a Wednesday night, and then I was in LA on Friday morning. It was crazy."