Angelina Jolie and Brad Pitt are reportedly set to marry before autumn

A source said: "Angie is expecting twins this fall, so it is making them feel a time crunch. They decided they'd both like to welcome their twin boys to the world as man and wife, which means the wedding has to happen fairly soon.

They've both realised how much they want to be together."

Angelina, 36, and Brad, 48 - who already have children Maddox, 10, Pax, eight, Zahara, seven, Shiloh, five and three-year-old twins Knox and Vivienne are said to have been through a rocky patch but finally came to the decision to wed after appearing together at last months Oscars.

The insider told Americas OK! magazine: "They had an amazing time Oscar weekend, since then, they've been madly in love.

"The wedding was totally off: They were having so many arguments, but they've finally managed to bury their differences.

Meanwhile, a third source says Angelina is planning to keep the pregnancy quite for as long as possible.

The insider said: "It's not something she wants to officially announce but she's at a point where she is telling a select group of people.

Angelina is really savouring every moment. She's having a tough time with morning sickness but says it's all worth it."