The 37-year-old actress is expecting her second child with husband Dave Galafassi, which is due some time next spring.
The couple confirmed their happy news in a statement, which read: "We are very happy to be expecting our second child together."
The couple - who married in 2003 - already have a two-year-old daughter, Sage Florence.
The Australian actress has previously admitted she is terrified of dying because she worries about what will happen to her friends and family when she has gone.
She said recently: "I think about it a lot, you know, what`s going to happen. I guess it`s the fact that I won`t exist and I won`t be around people that I love. I suppose my worst fear is that I don`t know what happens afterwards - it`s the ultimate unknown.
"I think the nearer I get - and I am getting closer to it, I accept that - it doesn`t make me freak out so much anymore. But I think the sooner I fully accept it, the sooner I will fully immerse myself in life."
Toni and Dave have homes in both Australia and Ireland and split their time between the two.