George Clooney is used to being mobbed by fans at premieres and shopping centres.

But when one lone fan spotted the Oscar-winning actor riding his motorcycle in Italy, she couldn't contain her hysteria, much to the amusement of Clooney.

The avid motorbike enthusiast, 47, was hoping he wouldn't be recognised as he rode through the streets of Portofino in a helmet concealing his famous face.

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But one mature fan was clearly aware of the A-list star's presence and screamed with joy as he drove past her.

As The Perfect Storm actor tried to keep a straight face, he soon burst into laughter at the sight of the lone blonde's hysterical behaviour.

Clooney is currently touring the Mediterranean on his luxury yacht, and has stopped off in St Tropez and Eze in the south of France, as well as Sardinia and the Tuscan coast of Italy.

He also owns a holiday home on the shore of Lake Como in northern Italy.

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Last week, he hosted Cindy Crawford and her husband Rande Gerber on the yacht, with the three of them stopping off to visit U2 frontman Bono at his hillside villa in Eze.

Despite his lengthy vacation, busy Clooney has found time to sign up to produce several films, including the big-screen adaptation of Jonathan Mahler's The Challenge.

On Saturday, he publicly expressed his condolences to his Ocean's trilogy co-star Bernie Mac, who died that morning of complications from pneumonia.

He is expected at the Venice Film Festival in three weeks for the world premiere of his new film Burn After Reading, which also stars his friend Brad Pitt and Michael Clayton's co-star Tilda Swinton.

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