Sienna Miller. (AP Files)

Sienna Miller is worried people see her as "not a particularly nice person" following her affair with married father-of-four Balthazar Getty.

The Factory Girl actress found herself at the centre of a major scandal involving Getty after he reportedly cheated on his wife with her in 2008.

She faced a barrage of negative press about the romance, and the couple eventually split earlier this year.

But gossips have since speculated the relationship is back on after Miller and Getty were spotted sharing a romantic break in Italy in June.

The British star has now accepted her actions have marred her reputation, telling GQ magazine, "I probably seem like not a particularly nice person, not a girl's girl. I think if you put a camera in anyone's life and document it daily for six years, from the age of 21 to 27, there are going to be things that aren't always pretty."

But Miller insists her "sexually manipulative" tag is unfair, adding: "I'm supposed to be this complete slapper (promiscuous woman), that's my reputation. But actually I was in a relationship from 19 to 21 with (the fashion designer) Dave (Neville), 21 to 24 with Jude (Law), then 25 to 26 with Rhys (Ifans), and then Balthazar. And then a few dalliances, three months here and there, but I've never been like a sh****r."