Scarlett Johansson gets tested for HIV twice a year. The Black Dahlia actress insists she is not promiscuous but has the test because she is "a responsible human being."

Scarlett, 25, revealed to 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 disgusting when people don't. It's so irresponsible. But contrary to popular belief, I'm not promiscuous."

The Scoop actress - who is dating her The Black Dahlia co-star Josh Hartnett - also claims that monogamy goes against nature because people "are like animals." But despite her liberal views on sex, Scarlett insists she is happy beingwith just one man.

She added: "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."

Scarlett insists she is very happy with Josh and has no plans to be single again anytime soon. She gushed: "Josh is very sweet. He's a good boy. A great person. I'm very lucky and I'm very happy. 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."

She added: "I mean, I went through periods of time when I was single. But when I'm in a relationship, I'm in a relationship."