A rep for the star has confirmed that she is indeed pregnant with her partner, David Gardner, a British sports agent who is reportedly a close friend of David Beckham.
Liv already has a child, Milo William, with her ex-husband, British musician Royston Langdon. She gave birth to Milo, now nine, in December 2004, but split from Langdon four years later.
The 37-year-old star, daughter of Aerosmith rocker Steve Tyler, only went public about her relationship with sports agent Gardner in August, but the baby announcement tells us that it's definitely serious!
The story continues after the video.
The couple appear to have been keeping their relationship on the down-low, although showbiz paps have spotted them out and about together several times in the past few months.
A source told E! that they were first set up by Brit supermodel Kate Moss - and her matchmaking skills certainly appear to have worked their magic in this case.
And if Gardner, who has two children from a previous marriage, ever needs any advice about fatherhood, he need look no further than his close friend David Beckham, who earlier this week shared his pearls of parenting wisdom with the Duke and Duchess of Cambridge. Celebrities - they're just like us!
Rumours had been swirling since the Incredible Hulk actress was seen trying to cover what looked like a baby bump while out in New York earlier this week. Liv has yet to comment personally on the baby news.
In the past Liv has made no secret of how much she enjoyed pregnancy, telling Self magazine back in 2008 that being pregnant was an 'amazing feeling'.