A private jet circled for 90 minutes just to allow Michelle Williams time to sleep.

The actress travelled from New York - where she had been doing promotional work on her new film 'My Week with Marilyn' - to Detroit by private jet to join the set of 'Oz: The Great and Powerful' last week, and because of her lack of sleep, her team arranged it so the pilot wouldn't land and wake her.

A source told the New York Post newspaper: "They had the plane circle so she could sleep as long as possible. Then she went straight to the set. She's had 5am call-times."

Michelle - who is also a single mother to six-year-old Matilda, her daughter with the late Heath Ledger - then had to fly back to New York on Sunday (13.11.11) for the premiere of 'My Week with Marilyn'. The week before that, she was on the opposite side of the US for a special screening of the film in Hollywood.

The 31-year-old actress has admitted when she played iconic screen beauty Marilyn, part of the screen icon's character rubbed off on her, making her "needier."

She said: "She was someone who so needed people and was always being abandoned.

"I found that, playing Marilyn, I became a lot needier than I actually am as a person. I needed quite a lot from people. An embarrassing amount."