Jessica Hart Reveals She Is Pregnant 6 Months After Birth of Daughter: 'Gonna Be a Wild Ride'

Jessica Hart is awaiting another bundle of joy!

The Australian model, 35, announced on Instagram this week that she is pregnant, expecting a baby with her race car driver fiancé James Kirkham. The news comes about six months after Hart and Kirkham welcomed their first child together, daughter Baby-Rae, on Nov. 17. (He is also dad to 7-year-old daughter Wren.)

"I just found out that I'm pregnant again, which is exciting," Hart says in the video, adding that she's "only about six weeks" into the pregnancy. "Now, after the initial shock of having two babies under 2 — Baby will be 14 months when baby No. 2 arrives. James and I are really excited now, but it's a big thing."

"The biggest thing for me right now is I'm immediately pregnant and breastfeeding, so making sure I'm getting like the best and most-nutrient foods I can is probably my No. 1 priority right now," she continues. "And for those of you who don't know, I'm predominantly vegan, so that's something I'm going to start looking more into and really make sure I'm doing the right thing, taking the right vitamins and supplements."

Want to get the biggest stories from PEOPLE every weekday? Subscribe to our new podcast, PEOPLE Every Day, to get the essential celebrity, entertainment and human interest news stories Monday through Friday.

RELATED GALLERY: Who's Due Next? Celebs Who Are Expecting

"I'm sure this will be great and everything's gonna be fine," the mom adds. "... I'm really excited to be going on this journey. I'm really excited for them to have each other. ... This is it. We're gonna have two kids under 2. It's gonna be a wild ride."

On his Instagram page, Kirkham shared a photo of the positive pregnancy test, captioning it with a simple red heart emoji.

In December, Hart opened up to PEOPLE about life as a new mom and explained the meaning behind her baby girl's name. "I think I'm doing really well," she said of mom life at the time. "We're very much still in our little newborn bubble. I don't know what's going on with the world at the moment. It's just me and her getting through each day. We're both learning together. It's really cool."

"Unfortunately the poor little thing has colic so we have days with endless screaming that we can't do much about, but even that isn't that bad," added Hart. "She can do no wrong in my eyes!"