By Adam Fleming
Political reporter, Daily Politics
Ms Witherspoon brought a touch of glamour to the House of Commons
Political journalists do not often find themselves sitting alongside reporters from Vogue, Marie Claire and Good Housekeeping at news conferences.
But that is what happens when Hollywood comes to Westminster in the shape of Legally Blonde star Reese Witherspoon (who reportedly commands $20m per film).
The actress, who won an Oscar for her role in Walk the Line, was drafted in by the charity Refuge to launch their new campaign against domestic violence.
The charity says it is difficult to gauge the seriousness of the problem, because victims are frightened to come forward and it is not a specific criminal offence in itself.
One in four women will be the victim of abuse from a partner or family member, according to the British Crime Survey.
'Suffered in silence'
Campaigners say that globally it outstrips cancer and car accidents as the biggest cause of death among women aged 19 to 44. Two women die from domestic violence each week in the UK, they estimate.
But research commissioned by the cosmetics company Avon, which has teamed up with Refuge for the campaign, suggests that 92% of people say they do not know anyone who has been affected by it.
"I've seen so many people who've suffered in silence, or been embarrassed or ashamed. It's not just an issue that affects a certain class or a certain race," Reese Witherspoon said.
She became the 1,353rd person to sign a petition calling on the UK government to improve services for victims.
She would not be drawn on whether any fellow celebrities had found themselves in violent relationships but admitted that a close friend had suffered at the hands of a former boyfriend.
"She felt intimidated and ashamed. And I was lucky enough to be in a situation where she confided in me," she said.
The Home Office recently launched a new strategy to tackle domestic violence - from 2011 children will be taught about abuse at school and an advertising campaign will be aimed at teenagers.
The visit to help the subject be brought up at prime minister's questions when Gordon Brown told the Commons there had been a 64% reduction in domestic violence and that more cases were reaching court.
But the showbiz magic did not rub off on the PM, who had to correct himself after referring to "Renee" Witherspoon.