Colour chameleon Nicole Kidman goes brunette for first scenes in Genius as she slips on UGGs and padded jacket in Oxford

She's been from honey, to strawberry to chocolate in the space of a month.

And it seemed like Nicole Kidman was rather enjoying sampling all of the shades when she stepped out in a brown wig on the set of new movie Genius on Thursday.

Following the appearances of co-stars Jude Law and Colin Firth, Nicole's hotly-anticipated first appearance in character came at Didcot Railway Centre as she arrived in a pair of UGG boots and a long, padded jacket.

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Something new: Nicole Kidman steps out onto the set of Genius in Didcot wearing a brown wig and UGG boots

Something new: Nicole Kidman steps out onto the set of Genius in Didcot wearing a brown wig and UGG boots

Nicole appeared to still be getting into character as Aline Bernstein as she swamped her slender legs with black UGG boots and draped a charcoal jacket around her slight frame. 

Her brunette wig - covering her recently returned fiery locks - was pinned at the sides into relaxed waves, while the colour made her light blue eyes pop.

The film is based on the book Max Perkins: Editor Of Genius, for which Kidman will play Thomas Woolfe's mistress Aline in the biographical story of his literary editor Max. 

Ready to go! The actress wrapped up in a quilted jacket ahead of her first scenes for the new movie

Ready to go! The actress wrapped up in a quilted jacket ahead of her first scenes for the new movie

The autumn 2015 release film sees Nicole star alongside a familiar face, with Colin Firth taking the helm as Max.

Colin and Nicole have worked together on recent projects including The Railway Man as well as this year's Before I Go To Sleep. 

The film explores the complex relationship between Max and Thomas Wolfe, played by Jude Law, and Ernest Hemingway, portrayed by Dominic West, who are both authors whose work Perkins oversaw.  

Reunited: Nicole gets to work with Colin Firth again on the latest project as he stars as Max Perkins 

Reunited: Nicole gets to work with Colin Firth again on the latest project as he stars as Max Perkins 

It is an adaptation of the Andrew Scott Berg book, written about Perkins' time at the publishing house Scribner.

The film has been a project that was long in the works, with Colin Firth and Michael Fassbender signing up in 2012.

Nicole joined the cast at the start of this year when Fassbender was replaced by Jude Law.

Jude and Colin have been spotted filming in West Sussex and Manchester, while Nicole is only just beginning production on her role.

Star-studded: Jude Law replaces Michael Fassbender in the movie, to play author Thomas Wolfe

Star-studded: Jude Law replaces Michael Fassbender in the movie, to play author Thomas Wolfe

Distinguished: The story, adapted from the book Max Perkins: Editor Of A Genius, follows the relationship between literary editor Max and the works of Ernest Hemingway and others

Distinguished: The story, adapted from the book Max Perkins: Editor Of A Genius, follows the relationship between literary editor Max and the works of Ernest Hemingway and others