London, Sep 2 - Model Heidi Klum has posed for a series of nude pictures for a soon-to-be-released coffee table book called 'Rankin's Heidilicious' and she describes the tome as 'very naughty'.

She has teamed up with renowned photographer Rankin for book, which is due to hit stores in October.

'It's very naughty. I've been shooting with Rankin, for seven years and working with him is fun because he always makes me look different. He always gets me to take my clothes off for some reason. We'll do some job and then he'll say, 'Why don't we shoot some more things?' and I'll wind up without anything on,' contactmusic.com quoted Klum as saying.

Heidi, who raises three children with her musician husband Seal, is pregnant.