Angelina Jolie adopts classic Old Hollywood look in stunning new ad campaign

A demure-looking Angelina looked every inch the old school Hollywood beauty with her shiny brunette hair piled loosely on top of her head, while wearing a classic LBD from the American luxury label.

The shoot took place several weeks ago, before the actress' bump confirmed reports that she was pregnant with twins.

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Classic: Angelina Jolie strikes a classic pose in the new spring campaign for US womenswear label St. John

U.N. goodwill ambassador Angelina took the modelling job along with a spokesperson role as the voice of the company's charity, which was created in support of children's issues and causes.

"She's a mother, actress and a philanthropist," said Richard Cohen, chief executive officer of St. John.

Jolie, 32, signed with St. John in September 2005. At the time, she said she was excited about working with the clothing line.

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Pregnant and proud: Angelina unveiled her baby bump at the Independent Spirit Awards last month

"I am a working mother who has set goals to accomplish a lot in this world," she said.

"I want my wardrobe to be beautiful, sexy and comfortable — all at the same time. St. John is all of those things."

Brad Pitt and Angelina are also adoptive parents to Zahara, three, Pax Thien, four, and have a biological daughter Shiloh Nouvel, 21 months.

In preparation for the birth this summer, Pitt has been rescheduling his work so he has enough time to spend with Jolie and the children.

A friend of the couple told the Mail Online: "They're having twins, Angelina is healthy, and he's thrilled that he's going to be a father once again.

"Brad's telling everybody close to him, because he's having to change around his work schedule to get ready for the birth.

"They didn't exactly plan this pregnancy, but they wanted more children and Brad says Angelina was very willing to have them herself."