18/08/2011 11:11 BST | Updated 18/10/2011 06:12 BST

Keira Knightley Battles For Role In 'Romeo And Juliet' Spin-off 'Rosaline'

PRESS ASSOCIATION -- Keira Knightley and Lily Collins are apparently battling it out to star in Rosaline.

The British actress is the first choice of Fox film studios and producer Shawn Levy to play the title character, although Lily - who appeared in The Blind Side - is a strong contender, reported Vulture.

The film, based on the as-yet-unfinished debut novel When You Were Mine by Rebecca Serle, focuses on the spin-off from William Shakespeare's Romeo and Juliet, but told from the perspective of the normally silent Rosaline, who falls in love with Romeo's cousin Benvolio.

Michael Sucsy is attached to direct the period romantic drama, which has been written by (500) Days Of Summer screenwriters Scott Neustader and Michael H Weber.

Author Serle admitted she has no preconceptions over the casting possibilities, saying: "I did used to be a really big fan of that brown-haired girl on that show Roswell [Shiri Appleby].

"But I'm going to be totally honest: I guess I saw her as a little bit of myself," she added.