Twenty-four hours as hectic as this could break a lesser man.

But George Clooney was certainly up to the task. After all, basking in admiration is all in a day's work for a movie star.

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Roll out the red carpet: George Clooney with Renee Zellwegger last night

Gordon and Sarah Brown were delighted to welcome Clooney, who looked Hollywood fresh despite a rather late night socialising with his old friend Mariella Frostrup and his newer friend Jemima Khan.

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I only have eyes for you: Clooney is enchanted by Jemima Khan

The Prime Minister, Clooney later said, had been "amazingly helpful" when asked for his support to bring stability to Darfur.

The 46-year-old actor, a United Nations "messenger of peace", has become an advocate for the troubled region.

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Blondes have more fun: With Mariella Frostrup (left) and Lucy Yeomans

Then it was off to schmooze with Renee Zellweger, his co-star in Leatherheads, which premiered in London last night.

It was not known whether Miss Khan, 34, Hugh Grant's former girlfriend, was among the guests.

The pair certainly got on famously at a party in Clooney's honour hosted by Harper's Bazaar editor Lucy Yeomans on Monday evening.

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I'd do anything for you George: The lovely ladies battling to be Nancy in Andrew Lloyd Webber's new production of Oliver mob Clooney

Perhaps it was Miss Khan's easy familiarity with the ins and outs of Hollywood. Or her animated political views.

Then again, she was wearing a particularly low-cut top.

She was among a group of six who continued the party at Clooney's suite at the Dorchester.