Sombre style: Nicole arriving at London Heathrow yesterday ahead of her performance on the X Factor. Photo:Rex Features
We're assuming her downcast look has something to do with her recent split from Brit boyfriend Lewis Hamilton after four years together - but we hope she manages a smile for her performance on the X Factor this Sunday...
Look back at Nicole's top style moments here:
- 16 May 2011<p> Nicole rocks a LBD by Miskai Bangles at the 2011 Fox Upfront party, New York.</p>

- 11 May 2011<p> Nicole at the 2011 National Movie Awards at Wembley Arena, London.</p> <p> FYI she's wearing an Irina Shabayeva jersey dress from the spring/summer 2011 collection.</p>

- 4 December 2010<p> What were you thinking with those devil horns?! Nicole is barely recognisable at the Capital Radio Jingle Bell Ball in the O2 Arena, in London.</p>

- 18 November 2010<p> Nicole injects some colour into her look at the Playboy Energy Drink Launch at Funky Buddha, Mayfair, London.</p>

- 8 September 2008<p> Nicole received the improbably titled "Best Dancing In A Video" award at the 2008 MTV Video Music Awards.</p>

- 18 November 2007<p> Nicole at the 2007 American Music Awards held at the Nokia Theatre downtown LA.</p>

- 18 November 2007<p> Nicole at the 2007 American Music Awards held at the Nokia Theatre in LA.</p>

- 1 November 2007<p> Nicole opts for a tiny Jenny Packham number at the MTV Europe Music Awards 2007 in Munich, Germany.</p>

- 17 October 2007<p> Scherzinger looks positively regal in this purple asymmetric dress by Valentino at the Fashion Rocks event.</p>

- 9 September 2007<p> Scherzinger goes backless in Temperley for the MTV Video Music Awards 2007, Las Vegas.</p>

See Nicole's style by browsing our shopping carousel below:
Passion for fashion? Follow us on Twitter and become our fan on Facebook
