Scarlett Johansson has revealed she’s tested for HIV twice a year even though she’s in a steady relationship.

She told Allure magazine: “I get tested for HIV twice a year. … One has to be socially aware. It’s part of being a decent human, to be tested for STDs. It’s just disgusting behavior when people don’t. It’s just so irresponsible.”

But that’s not to say she’s cheating on boyfriend Josh Hartnett - or that he’s cheating on her: “Josh is very sweet. He’s a good boy. A great person. I’m very lucky and I’m very happy.

“Contrary to popular belief, I’m not promiscuous. There does seem to be a mistaken belief out there that I am sexually available somehow — which is not to say that I’m not open-minded about sex.”

“Yet I wouldn’t say I’m a serial monogamist, either. I mean, I went through periods of time when I was, ah, single. But when I’m in a relationship, I’m in a relationship.”

“I do think on some basic level we are animals, and by instinct we kind of breed accordingly. But as much as I believe that, I work really hard when I’m in a relationship to make it work in a monogamous way.”