Penelope Cruz had to wear a false butt in new movie "Returning."The Spanish siren - who plays a Sophia Loren-style housewife - strapped on the prosthetic bottom after movie bosses decided her own posterior wasn't curvy enough.

An insider is quoted in Scotland's Daily Record newspaper as saying: "Penelope's breasts were fine for the part but it was felt that she needed more curves down below."

"To make Penelope perfect for the part, we decided to fit her with a false bottom."

The 31-year-old beauty reportedly loved her new butt - and has begged producers to let her keep it once filming is over.

Meanwhile, Cruz - who is romancing actor Matthew McConaughey - has confessed she upsets her parents by going topless on screen.

The beauty, who has bared her breasts in no less than eight films, admits her hairdresser mother, Encarna, and merchant father, Eduardo, find it difficult to watch her peel off for the cameras.

She revealed: "Going topless is not my favorite thing. It was a little tough for my parents, but they saw that I wasn't being stupid about it."