ANGELINA JOLIE has dismissed reports she underwent fertility treatment to conceive her newborn twins with partner BRAD PITT.

The couple were rumoured to have turned to in vitro fertilisation (IVF) to help them expand their brood with twins KNOX LEON and VIVIENNE MARCHELINE, who were born last month.

But Angelina, 33, has hit back at the claims and says if she had gone through IVF she would admit it.

She said: "If they had been conceived through IVF, we would have been happy to discuss it. But we have been fortunate never to have had fertility problems."

The actress has starred in numerous films but she says motherhood is her most important role yet.

"My mom loved being a mom and made sure her children knew every day how much joy we brought to her. I hope to give that to my kids."

The twins became the fifth and six children to join the Jolie-Pitt clan. They are already parents to adopted kids MADDOX, six; PAX, four; ZAHARA, three, and biological daughter SHILOH, two.

The twins are said to be worth US$7 million each after celebrity magazines launched a bidding war for the first pictures of the duo.