Supermodel Kate Moss says that the late British artist Lucien Freud inked two small bird tattoos on her back during a portrait sitting.

In 2002, Moss posed nude for Freud while she was pregnant. His painting with her baby bump went on to sell for 3.9 million pounds ($6.2 million) at a Christie's auction in 2005.

A conversation began about Freud's stint in the Merchant Marine during WWII during which he tattooed sailors.

She says, “He told me about when he was in the Navy, when he was 19 or something, and he used to do all of the tattoos for the sailors. And I said, ‘Oh my God, that’s amazing.’ And he went, ‘I can do you one. What would you like? Would you like creatures of the animal kingdom?’ I said I liked birds and he replied, ‘I’ve done birds. I’ve got it in my book.’ And he pointed down at a painting of a chicken upside down in a bucket. And I said, ‘No, I’m not having that.’ And then he said, ‘Maybe I should just do you.’ And I thought, I’m not going to have a girl on my arse. So we decided to do a flock of birds.”

Moss had two tiny swallows tattooed near the base of her spine. She told Vanity Fair, “I mean, it’s an original Freud. I wonder how much a collector would pay for that? A few million? If it all goes horribly wrong I could get a skin graft and sell it."

For nine months, the model sat from 7pm to 2am, seven nights a week, for Freud to finish the painting.