Lindsay Lohan I Look Like a '70s Porn Star

7/31/2010 7:00 AM PDT BY TMZ STAFF
Lindsay Lohan revealed her darker side recently during a photo shoot for her upcoming porn star biopic "Inferno" -- and she did it all wearing nothing but your grandma's underwear.

Lindsay Lohan Porn Star - Inferno Pics
The photos were taken by well-known photog Tyler Shields ... but they're for promotional purposes only. The film -- in which Lindsay plays porn legend Linda Lovelace -- hasn't even been shot yet.