The Duchess of Cambridge wore this outfit back in December 2011 when she and Prince William visited the Centrepoint Camberwell Foyer facility. She paired an olive Ralph Lauren Blue Label turtleneck dress with her trusty Aquatalia Rhumba boots and a simple Reiss black suede waist belt. Kate completed the look with her Kiki McDonough Grace earrings.
The estimated cost of Kate's outfit is US$2100! After a little internet shopping, I've managed to put together this entire look for about 10% of that value! You can steal Kate's style for under US$220 :)