'The Hunger Games' star - who is already mum to 20-month-old Felix - announced the recent birth of her second son Magnus Mitchell with husband Max Handelman on her official website yesterday (14.11.12).
"Magnus joins older brother Felix, thus commencing a decade or more of close hand to hand combat. Like Felix, Magnus was born via gestational surrogate. This experience has exceeded all expectations, taught us a great deal about generosity and gratitude, and established a relationship that will last a lifetime.
"I am also so very thankful to our family and friends for their support throughout this process, as well as the Centre for Surrogate Parenting for helping make all this possible.
"I now turn my attention to managing two boys under two. For which I am thankful. And all their poop. For which I am less thankful. Wish me luck."
The actress previously opened up about her struggle to get pregnant.
Earlier this year, she said, "It was a womb issue for me. Embryos wouldn't implant."
She also admitted that using a surrogate was not an easy decision, saying, "It's a big leap, inviting this person into your life to do this amazing, important thing for you. And it's hard losing that kind of control. But our surrogate is so extraordinary, and she's still in our lives. She's like an auntie."
Elizabeth is currently filming the second movie in 'The Hunger Games' trilogy 'Catching Fire' alongside Jennifer Lawrence, Liam Hemsworth and Josh Hutcherson due to be released next year.