[caption id="attachment_90275" align="aligncenter" width="607"] Photo Credit: Getty Images[/caption]

There must be "Diamonds" in it: RiRi Woo, Rihanna's new lipstick for MAC Cosmetics, launched exclusively online yesterday and totally sold out in just three hours.

"Red lipstick all on da paper!!! #RiRiWoo #SOLDOUT #3HOURS #lookatyou #nowlookatus," the singer tweeted Thursday afternoon.

Rihanna's collaboration with the makeup company will ultimately result in four collections, known as RiRi [Hearts] MAC. Plans call for new lines in summer, fall and during the holidays.

Now we just worry this will start a beef with Nicki Minaj, whose Viva Glam Nicki lipstick has been a top-seller for MAC.