Halliwell was originally going to wear an all-black dress , but she thought it was too boring so her sister sewed on a Union Jack tea-towel , with a ' peace ' sign on the back , so as to not offend anyone . It was worn during the Spice Girls ' performance of their number one song " Who Do You Think You Are " . Later on she sold her dress in a charity auction to Hard Rock Cafe in Las Vegas for a record £ 41,320 , giving Halliwell the Guinness World Record for the most expensive piece of pop star clothing ever sold . The performance won Most Memorable Performance Of 30 Years at the 2010 Brit Awards
2010 Brit Awards
2010 Brit Awards
1997 Brit Awards