Victoria visited South Africa in February this year to learn about antiretroviral clinics in Cape Town, which help mothers reduce the risk of passing on HIV to their children as well as suppressing the virus in those already infected.

She commented yesterday that "I've always been involved [in AIDS campaigning] but in the background. And when I was lucky enough to visit South Africa a few months ago, it changed how I feel. I came home thinking 'I have a responsibility.'"

She will work on a campaign which aims to help every child to be born HIV free. In August, Victoria sold 600 items from her own wardrobe on TheOutnet.com to raise money and awareness for mothers living with HIV in sub-Saharan Africa.

"I'm learning. I have people mentoring me. I'm going back to South Africa in a few week and then further afield next year. I'm doing everything I can do. I would do anything for my children and I think every woman has the right to do what she can for her children."

Victoria missed the opening of her first flagship store to speak at the UN event, but her husband David Beckham visited the minimalist-designed store to welcome customers.

"As a woman and a mother I have a responsibility to support other women" Victoria Beckham is named a Goodwill Ambassador