So much for the 'Pob' - now actress Katie Holmes has chopped her hair even shorter than friend Victoria Beckham ever has.

But the lack of length hasn't hampered her diversity, with the young mother showing off a severe bob while on a film set - and then almost boyish curls while out with husband Tom Cruise.

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Mop top: 1930s-style Katie Holmes is picked up by husband Tom Cruise on the set of Eli Stone on Thursday

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The next day, Katie is straight-laced 1970s ...

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... While earlier in the week she was 80s-style Cagney and Lacey

The chop appears to have come just as American actress Eva Longoria cut her own hair in a style that was startlingly similar to both Katie and Posh - perhaps inspiring Katie's choice in an effort to stay one step ahead in the hair-raising stakes.

The actress seemed to be demonstrating great bobs of the 20th century with her new do while filming on the set of her movie 'Eli Stone' in Hollywood this week: starting with a Cagney and Lacey 80s bob, then moving to the 1930s-style mop top and finishing with the sleek and severe do that recalled the 1970s.

When her famous husband conscientiously showed to pick her up on Thursday night, she stepped out with a mop top that was arguably more reminiscent of British tennis player Andy Murray than Victoria Beckham.

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Katie's new do is reminiscent of another famous mop top, British tennis player Andy Murray

But, appearing on set again the next day, she took on a far more severe aura with a straight and short look.

WAG and Spice Girl Victoria was the first to lop of her signature hair extensions in August, 2006 for a cropped bob hairstyle, coining the phrase 'pob' - meaning 'Posh bob'.

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Eva, Posh, Katie: Devotees of the 'Pob'

Nine months later, Posh's pal Katie followed suit with her own take on the pob and this week their friend Eva caught on to the trend - though Eva's waves meant her style was more similar to Katie's than to Posh's poker straight look.

Watch this space ... how Posh and Eva react to the new do could start a whole new trend.