The identity of the photographer who took pictures of Kate Middleton sunbathing topless is still a secret, but another photojournalist says he knows who did it.

Celebrity photographer Pascal Rostain told the Herald Sun he and other paparazzi photographers know who got the controversial shots of the Duchess of Cambridge, but he won't reveal the name.

"In our small paparazzi world, we know who it is but obviously don't say anything," Rostain said.

He did give a hint about the identity of the photographer some British tabloids have labeled "Le Rat."

"I can just say it is an Irish national who lives in the south of France," he said.

Rostain did explain how transactions typically work when photographers get scandalous pictures like the one of Middleton's topless sunbathing.

"[A magazine] commissions a photographer or an agency ... the price is fixed in advance, it can be 1000 euros ($1245) for every working day plus expenses and a few thousand euros for the snaps," he said.

Another possibility, he said, is that the photos were not commissioned but instead a photographer took the pictures independently and offered them to various magazines for several thousand euros.

French magazine Closer, which first published the pictures, has said it did not commission the photos and simply purchased the rights to exclusively publish the pictures first. If that's the case, the magazine does not own the photos and likely does not have possession of the original files.

The topless photo controversy isn't the only magazine scandal surrounding Middleton in the last few days.

American magazine Star published a photo on its cover that showed the duchess with a baby bump and claimed she was pregnant with twins, but conflicting reports have said the magazine may have doctored the photos and expanded her belly to make it seem she is pregnant even though she actually isn't.

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