The reality TV star - who was known as Bruce Jenner before her gender transition has joined forces with the make-up brand to launch a rose lipstick called Finally Free.
100 per cent of the profits from the product will go to the MAC AIDS Fund Transgender Initiative to support its work in support of transgender communities.
Caitlyn said in a statement on the company's website: ''MAC was the first to come to me, and a company i realized, would really make a big commitment. I knew the Viva Glam campaigns, i saw that the proceeds were going, in those cases, mainly to AIDS and HIV causes, and I was wondering if they were interested in doing something specifically geared toward trans issues because we need funding. MAC is a global company. It's in places around the world where not just trans issues, but women's issues, are a major subject that you have to talk about.''
Caitlyn joins a host of stars including Rihanna, Nicki Minaj, Lady Gaga and Pamela Anderson, who have all released their own lipsticks with MAC.