Actress Vidya Balan says she is obsessed about cleanliness, but went without washing her hair for a week for her role in "Kahaani 2".

"For 'Kahaani 2', there were actually days when I didn't wash my hair for seven days and that's a big deal for me because I am obsessive about cleanliness," she said during CNN-News18 Bollywood Roundtable with Rajeev Masand.

She also spoke about child sex abuse, a subject dwelled upon in "Kahaani 2".

"Child sex abuse is something I feel very strongly about, but I never thought I would have the courage to tell a story about it on screen," said the National Award winner.