Pregnant ... Yahoo CEO Marissa Mayer is expecting twins. Picture: AP Source: AP

Mayer says on a posting on her blog that she and her husband are expecting the twin girls in December.

“I have some exciting news to share — I’m pregnant!” she says on her Tumblr posting on Monday night.

She says that she will take just two weeks off after the birth and will work during the pregnancy as she did with her son’s birth three years ago.

Mayer says that she’s informed Yahoo executives of her pregnancy.

Three years ago, Mayer announced she was pregnant with her son on her social networking accounts just a few hours after Yahoo hired her as its third fulltime CEO in less than a year.

Mayer dated Google founder Larry Page in the early 2000s but married lawyer Zachary Bogue in December 2009. They have a son named Macallister.

Married ... Marissa Mayer and her husband Zachery Bogue are expecting twins. Picture: AP Source: Supplied