Foreign secretary William Hague will travel with Hollywood actress Angelina Jolie to Africa this week to raise awareness of warzone rape.
Hague and Jolie will visit survivors of rape and sexual violence on a tour of the Democratic Republic of Congo and Rwanda, said the Foreign Office.
The pair are expected to call on all governments to help eradicate sexual violence in conflicts when they meet local political leaders.
Angelina Jolie has worked with Hague before, launching the UK's Preventing Sexual Violence Initiative in London last year.
Her 2011 film In The Land Of Blood And Honey depicted the experiences of women in the rape camps set up during ethnic cleansing in Bosnia-Herzegovina, and was a catalyst for the new initiative, the Foreign Office said.
Angelina Jolie said: ""This visit is about hearing first hand from people who have endured rape and sexual violence during the conflict in the Eastern DRC.
"We want to identify ways in which the international community can help them to rebuild their lives.
"Unless the world acts, we will always be reacting to atrocities, treating survivors rather than preventing rape in the first place.
"I welcome the United Kingdom's efforts to galvanise the international action that is so desperately needed."
The visit comes three weeks before the foreign ministers meet in London with their counterparts in the US, France, Canada, Japan, Germany, Russia and Italy for the annual G8 summit.
William Hague said: "Rape is often used as a weapon of war in conflict zones around the world. It destroys people's lives and communities in the most horrific manner imaginable.
"Yet more often than not the international community looks away, the perpetrators of these brutal crimes walk free and the cycle of injustice and conflict is repeated. We have to shatter this culture of impunity."
Hague and Jolie will urge G8 members to agree landmark measures to secure justice for survivors of sexual violence and deter perpetrators.