The international development secretary and the glamorous pop singer are supporting an initiative to reduce numbers of women who die in pregnancy.

Ms Short told the charity event that more than 600,000 women die each year as a result of pregnancy and childbirth, 99% of them in developing countries.

And she called for a worldwide effort to improve education, contraception and medical facilities in some of the world's poorest countries.

Ms Short said: "The international community has set itself a target of saving eight million women's lives between now and 2015. This is an achievable target and we can do it if we have the political will."

'We're proud'

She also praised the former Spice Girl for her new role as a goodwill ambassador for the UN, promoting better contraception in developing countries.

She said: "Thank you on behalf of us all for taking on this job. You will be able to do an enormous amount of good and we are all really proud and pleased you are doing it."

Ms Halliwell refused to give interviews at the function, at the House of Commons, but her spokesman said: "She is just here in a private and personal capacity to show her support."

Two of Geri's former Spice Girl partners are expecting babies.

The reception was organised by the charity Marie Stopes International, which promotes access to modern contraception, improve health care and reduce the number of unsafe or illegal abortions.

The event marked the 10th anniversary of its Safe Motherhood Initiative.