Rihanna is having an exciting birthday week. A few days after she debuted her first fashion collection Rihanna for River Island during London Week, the chart-topping singer has announced that she has inked a deal with MAC Cosmetics.

The Diamonds singer tweeted a picture that offered a sneak peek of several products fans can expect from her new MAC line the day before her 25th birthday on Tuesday, Feb. 20.

"That's right baby, I'm a #MACgal now!," she captioned the photo. "Get into it, package designed and products created from scratch by yours truly! Thanks to the EPIC team at #MAC for giving me the opportunity to play and share my favorite sh*t with my fans and yours."

Rihanna went more in-depth about the MAC deal in an interview Women's Wear Daily.

'When you think of makeup, the brand that pops into your mind-for something legit-is MAC. Whatever color you want, it's like, "Let's go to MAC"', Rihanna told WWD. 

"I've been using MAC on tour for such a long time, it was a natural fit for me. I have always loved makeup, and I always said that if I do it, I want to do it with a credible brand."

The first product set to be released will be called RiRi Woo, a lipstick inspired by her favorite MC lipstick Ruby Woo. The collaboration is the first time that MAC has signed on a celebrity to launch their own signature product that is not under their famous VIVA GLAM campaign.

John Demsey, group president of the Estée Lauder Cos. Inc., MAC's parent company, told WWD that their business relationship with Rihanna is a "long-term one that involves the development of four distinct color initiatives."

The four collections, called RiRi [Hearts] MAC, will be sold at her concerts and online beginning this spring. The second collection will follow in the summer, and will also be sold online. A third will arrive in retail stores in the fall, and the fourth will come out during the holidays and will be available for retail purchase in stores.  

The summer collection includes two more lipsticks, a Lustre Drops eyeshadow and a powder blush duo. The fall collection include four lipsticks, a Lipglass version of RiRi Woo, two eye shadows and false lashes. 

Rihanna also leaked a photo for her Rihanna for River island ad campaign. One image featured a group of models wearing 90s-inspired separates that include denim, dresses, crop tops and thigh-hi slit skirts while posed against a bright blue and purple background.

The Rihanna For River Island campaign pictures were also posted in Britain's Mirror. One steamy shot features supermodel Jourdan Dunn who attended the runway show and partied with the superstar at her afterparty.

Tags: Rihanna MAC Rihanna For River Island