The invitation list is typical of the star-studded soirees that have placed Elisabeth Murdoch at the pinnacle of London's most glamorous party circuit. Later this month, the Oscar-winning actress Gwyneth Paltrow will rub shoulders at Ms Murdoch's home with, among others, a Swedish heiress, the fashion director of Vanity Fair and the River Café co-founder Ruthie Rogers .

But what may seem just another gathering of the capital's mid-Atlantic glitterati at the Notting Hill house that Ms Murdoch shares with her husband, Matthew Freud, the PR guru, was given global political significance yesterday when it was announced that the occasion in question is a fundraiser for Barack Obama, with attendees paying up to $2,300 (£1,160) each into the American presidential candidate's campaign fund.

The fact that the host for the event is the second daughter of Rupert Murdoch provoked immediate excitement on the other side of the Atlantic, where the political favour of the 77-year-old media mogul and his dynasty has long been a subject of debate. The New York Times declared yesterday that the London social event offered "possible clues to Hillary Clinton's Murdoch status".

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Until recently, it had been assumed that Mr Murdoch had conferred his favour on Mrs Clinton after he organised a fundraiser for her, and his New York Post newspaper endorsed Mr Obama's rival for the Democrat candidacy for a second term as New York State Senator in 2006.

The rapprochement between the magnate and the former first lady seemed complete last year when he made a donation to her campaign. His son James also gave $3,450 to Mrs Clinton.

But now it seems the Murdoch political wind has decisively changed direction. The New York Post has been a harsh critic of Mrs Clinton throughout her campaign and now, to add insult to injury, one of the stars of the Murdoch clan, who holds both American and British citizenship, is acting as transatlantic cheerleader for the Democrat frontrunner.

The list of confirmed attendees for the Elisabeth Murdoch gathering on 28 April reads, predictably, like a roll call of London's Anglo-American movers and shakers, with film stars and a speechwriter for the former United Nations secretary general Kofi Annan jostling for space alongside investment fund managers and property developers.

A flyer for the Obama fundraiser names Ms Murdoch, the woman once declared the world's most powerful blonde by Tatler magazine as one of 12 "event chairs" alongside Ms Paltrow, Ruthie Rogers and Cristina Stenbeck, a leading Swedish businesswoman and heiress.

A list of 20 "event hosts" includes Kay Saatchi, the ex-wife of the art mogul Charles Saatchi, Joanna Shields, the president of the social networking website Bebo, Elizabeth Saltzman Walker, the fashion director of Vanity Fair, and David Blood, who runs an investment fund with the Nobel Prize-winning former US vice-president Al Gore.

Potential guests, who are warned "RSVP required – space is limited", are invited to pay the $2,300 fee to attend a "VIP reception", or $1,000 to appear at the main reception an hour later. Anyone hoping to attend who does not hold an American passport will be disappointed because only US citizens can contribute to a presidential campaign.

The key role of Ms Murdoch, 39, in the event will cement her growing importance as a public and business figure. Her Shine television production company recently became one of Britain's most influential "super indies" after it acquired three rivals including Kudos, the maker of Spooks and Life On Mars, and Reveille, the American company behind Ugly Betty and the US version of The Office.

But last night, those close to the burgeoning entrepreneur played down any wider significance to her support for Mr Obama. Speaking from his yacht in the Caribbean, Mr Freud told The New York Times: "I don't think you can interpret the event as anything other than she is enthusiastic about Obama's campaign."