Angelina Jolie and her partner Brad Pitt are reportedly looking to double up with another set of twins.

Hollywood's hottest couple are said to be working on extending their brood only six months after Angelina gave birth to Vivienne and Knox.

A source tells Star, "Angelina is taking prenatal vitamins, visiting her ob-gyn, undergoing secret fertility treatments and gearing up for another set of twins.

"Angie's doctors told her that she has a strong chance of conceiving twins if she does it within two years after having her first pair."

The source adds, "She's been seeing a fertility doctor regularly. She and Brad are monitoring when she's fertile.

"And they're trying really hard in the bedroom!"

We bet!

See Brad and Angie's family album below