The 28-year-old blonde, who has been in showbiz since the age of three, says baring her body in new crime drama All Good Things was simply no big deal.
"I forgot I even did it," Dunst told Fox News's Pop Tarts.
"I don't even think about it. We really got to know each other through eight weeks of rehearsal, it was important we felt very comfortable with each other."
The upcoming film chronicles one of America's most notorious missing person cases - that of real estate mogul Robert Durst who was suspected but never tried for killing his wife Kathie in the 1980s.
Starring opposite The Notebook star Gosling, Dunst takes on the role of Kathie.
It is hoped the gritty flick can help solve the real life murder mystery by uncovering fresh clues.