Mischa BartonTake cover, Mischa Barton is NOT happy.

What's got her goat?

Well, according to Female First, Mischa is fuming about pics that have surfaced of her sunbathing topless while on holiday in Australia.

And she's letting the paparazzo who took the pics really feel her anger.

So what's happening?

The snaps, taken by papster Jamie Fawcett, have apparently appeared in a magazine and online Down Under.

Mischa has reportedly said: "He's a ridiculous human being. I've never abhorred anyone more. I was so angry, I went up to him and said how disappointed I was with his behaviour. He apologised but he was very insincere."

Pap Jamie has had his say too and has told the Sydney Daily Telegraph that he did warn Ms Barton before he took the snaps and apparently told her to find a private spot.

He said: "We spoke to each other on the island, and that's when I showed her my camera and I hadn't taken any shots of her topless.

"I did warn her it was a public place, and if she wanted privacy she shouldn't be there."