Sienna Miller. Photo / Reuters

Sienna Miller. Photo / Reuters

Sienna Miller will always sunbathe topless - because she is European.

The 25-year-old actress was recently photographed topless on a Mexican beach with rumoured new boyfriend model Jamie Burke.

Sienna insists she has no shame about baring her breasts while on holiday because it is a natural thing to do.

She said: "I'm not saying it is necessary all the time but I'm a European and I have a European mentality about these things.

"If I go to a beach, I don't wear a top. I would find it strange."

Sienna is just as comfortable showing off her body on screen.

The blonde actress' sex scenes with co-star Hayden Christensen in new film Factory Girl were so realistic they sparked speculation the pair had romped for real.

Sienna vehemently denied the claims, saying: "We're making a film about real people having real sex. So the film's making tons of money, but it's NOT a real sex scene.

"I'm not going to have sex in front of 20 people on set!"

In the film, Sienna plays artist Andy Warhol's tragic muse Edie Sedgwick.

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