Rihanna celebrated her birthday on Wednesday by signing a massive new deal with MAC Cosmetics.

The singer's first product, a lipstick called RiRi Woo, will be released to coincide with the start of her Diamonds Tour in Brooklyn, New York City in May.

Rihanna tells Women's Wear Daily, "When you think of make-up, the brand that pops into your mind - for something legit - is MAC. Whatever color you want, it's like 'Let's go to MAC.' I've been using MAC on tour for such a long time it was a natural fit for me. I have always loved make-up, and I always said that if I do it, I want to do it with a credible brand."

In a post on her Twitter.com page, the Umbrella hit-maker adds, "That's right baby, I'm a MAC gal now! 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 s**t with my fans and yours."

Products from the range will be released throughout 2013.

News of the deal comes just days after Rihanna's debut clothing collection, for U.K. high street chain River Island, was slammed by critics following her unveiling at London Fashion Week on Saturday.