Nicole Richie is putting her days as Paris' BFF far behind her by going solo and kicking butt on US TV.

The petite star swapped her trendy socialite appearance for a murderous one to guest star as a former cheerleader back for revenge in Chuck.  

Nicole plays Heather, a karate-trained villain whose dealings with the Russian Mob get her into all sorts of trouble.

In the bloody scene, Heather battles main character Sarah in the halls of their former high school.

See Nicole practising her gun toting skills below