Sienna Miller rocked an amazing, bright red lip in support of World AIDS Day in London. Now, you can copy her look and give back at the same time too.

The M·A·C AIDS Fund and the Viva Glam Program have teamed up with Lady Gaga and Cyndi Lauper to create two shades with a cause. Cyndi Lauper's sultry, red (pictured below) is the perfect way to get Sienna's makeup style with ease. Plus, by purchasing this M·A·C 'Viva Glam VII' Lipstick, every cent of the selling price is donated to the M·A·C AIDS Fund to support men, women, and children living with HIV and AIDS. Now, that is powerful beauty.