Helena Bonham Carter claims her breasts swelled to the size of melons then shrivelled to tangerines in her new film.

The actress fell pregnant during the filming of 'Sweeney Todd: The Demon Barber of Fleet Street', directed by her long-term partner Tim Burton, and revealed her breast size changed constantly in the final cut of the movie because it was filmed out of sequence.

Helena told Playboy magazine: "Anyone who pays attention to my chest size will see there's no continuity.

"The first half of filming I wasn't pregnant, and the second half I was, and because we didn't shoot it in order, I start off with huge breasts and then I walk upstairs and suddenly I've got tangerines again. It's melons to tangerines!"

The 41-year-old actress, who already has a four-year-old son, Billy-Ray with Tim, is due to give birth this month.

Helena plays Mrs. Lovett in 'Sweeney Todd: The Demon Barber of Fleet Street' which stars Johnny Depp as the murderous London barber.

Johnny has revealed he was terrified of singing in the musical film and had to take lessons from his French singer wife Vanessa Paradis.

He said: "I was more frightened than anyone, except maybe Tim Burton.

"I've never sung before in my life, so I kept it very low key and recorded a demo in my friend's garage studio. The first person I played it for before Tim was Vanessa who gave me tips on singing, since she is a singer."