Taylor Swift has been cast as Zac Efron’s love interest in a new movie.

‘The Lorax,’ based on the Dr Seuss book of the same name, will centre around a boy, Ted, played by Efron, who wants to discover how the world became so ugly.

Danny DeVito will play the title character while Betty White will voice Ted’s grandmother.

 'The Lorax' will be released in 3D next March.

Watch a brunette Taylor Swift make her acting debut in ‘CSI’ below.