Kristen Stewart

Kristen Stewart

Kristen Stewart went all out to portray rocker Joan Jett in the new Runaways biopic, even becoming left handed.

The young actress spent time with Jett, who was a consultant on the film.

The film centres around her famous girl band, and Kristen took time to study the rocker.

Impressed Jett says, "I'm a lefty too - not guitar wise - but in my handwriting and so she switched that up too; she started writing left handed."

The Runaways is set to hit U.S cinemas in March 2010 with England getting the film later in the year.

Stewart controversially cut her hair into a mullet style to fit the role.