The screen beauty has a sunrise etched onto the inside of her left arm, but insists she will never reveal the special meaning of it.
Scarlett - who is married to Ryan Reynolds - said: "I've had the tattoo of a sunrise on my arm for a while. It makes me happy when I look at it, but the reason I had it done is very personal. Some things have to remain private."
The 25-year-old actress loves experimenting with new looks and was thrilled when she had to dye her hair red for her role as a Russian spy in "Iron Man 2" - in which she stars alongside Gwyneth Paltrow, Robert Downey Jr. and Mickey Rourke.
She added: "I play Black Widow in 'Iron Man 2' and I had to dye my hair red to audition, which I loved. When I met the producers the second time I still had red hair because I was hoping they'd cast me, but also because I was experimenting with my hair color."