Rita Ora was ''obsessed'' with an illustration which she had tattooed to her rib cage.

The 'I Will Never Let You Down' singer, who already had a number of inkings, has gone topless on the front cover of the May edition of UK ELLE magazine and shows off the huge pin-up girl tattoo inspired by a Alberto Vargas image.

She told the magazine: ''It's based on an original piece by Alberto Vargas, who was an incredible illustrator in the 1930s.

''He was one of the creators of the pin-up image. That's our build, our power.

''That's why I was obsessed with it, learning what men don't understand about women and what women don't understand about men.

''I was obsessed with the painting a long time ago, and then I got it done six months ago.'

''I just love pretty things, whether it is art, a song or a pair of shoes.''

The 23-year-old star - who is dating DJ Calvin Harris - chose tattooist Bang Bang McCurdy to create the art work, which took five hours and was described as ''the most detailed tattoo'' he'd ever done for a celebrity.

He said at the time: 'The tattoo is on her right ribcage. It's big! When she's standing it's about seven inches tall, but when she's laying down it's about 10 inches, plus.''