Painting the town Scarlett

When Scarlett Johansson, Hollywood's latest hot property, arrived in London recently, she was ostensibly here to work. The 19-year-old star of Lost In Translation is spending a month in the capital as the female lead in Woody Allen's latest and as yet untitled movie, the plot of which is a closely guarded secret.

It is the first time the renowned director has made a film in London, and it has seen Johansson - who stars alongside Irish actor Jonathan Rhys-Meyers - working on location across the capital, mainly in Notting Hill, Marylebone, Bond Street and Belgravia. The film itself is said to be a gentle satire on young London society, a send-up of the vanities and indulgences of a monied and spoilt set, with even art collector Charles Saatchi reported to have been offered a walk-on part as himself.

It is rather appropriate, then, that outside work, Johansson has spent so much of her time since arriving here partying with the very people the movie parodies. In fact, she has cut a swathe through a party crowd which might loosely be termed "the Prince William set". It includes a smattering of William's ex-girlfriends, another young royal, society It-girls, pop stars and trendy clubbers - a fairly accurate cross-section of what now seems to constitute London society.

Rather like a 1920s American heiress on a European Grand Tour, Johansson has set up home at a Covent Garden hotel (complete with its own private screening room), where she is ensconced in a £1,000-anight loft suite. Decorated with Aubusson-style rugs, chintzy English sofas, antiques, an open fire and elaborate gilded mirrors, her suite is on two levels and has 15ft-high ceilings. The hotel is also a favourite of magician David Blaine and model Linda Evangelista.

In another attempt to immerse herself in London life, she and her entourage regularly order fish 'n' chips and mushy peas (£16.50) from room service and a breakfast of waffles with blueberries and mascarpone (£7.50). She is also borrowing Gwyneth Paltrow's London chauffeur while the Shakespeare In Love star is on holiday.

That Johansson - born in New York to European immigrant parents - has so effortlessly become an integral-albeit temporary) component of a privileged party set is, however, the result of some very careful planning. For the Evening Standard can reveal that just weeks before her arrival here, a number of very discreet phone calls were placed by Johansson's personal assistant to a host of pivotal people in London.

The reason is that - work aside - the young actress was concerned that her social life in London would be virtually nonexistent. The US media may have dubbed her "the hottest star on the planet", but she has few, if any, British connections. Her boyfriend, American actor Jared Leto - who dated Cameron Diaz for four years and is 13 years older than Johansson - is working in New York. Only last weekend, she paid a flying visit to Manhattan to spend some time with him.

Back in London this week to resume filming, Johansson is determined to keep having as much fun as she can (all in the interests of research, of course). So it was that one of the first calls made by Johansson's people was to Maurice Marshall, the discreet "fixer" who works exclusively at the trendy Soho nightclub Kabaret's Prophecy.

Marshall, a 37-year-old Londoner; just "Maurice" to those in the know, can get you in to virtually anywhere, and introduce you to anyone. Two weeks ago, as a result of being recommended to him, Johansson held a "girls' night out" at the club.

With Dom Perignon as the house champagne (£135 a bottle) and the lethal Kundalini Rani cocktail (cognac, champagne, vodka, lemon juice and raspberry sorbet at £10.50 a glass), Johansson invited six girlfriends, most of whom also work in the film business, to indulge in caviar and chips (reasonable, at £5) and Kobi beef burgers (£7), followed by frozen strawberries dipped in milk or white chocolate (£4). She has also been a regular at the painfully discreet Funky Buddha, another West End nightclub, but has avoided Footballers' Wives-style haunts such as Tramp.