Tim, 37, also followed with a post.
"I've fallen in love twice all over again with these two!!! I just LOVE LOVE LOVE our little Elle Robards," he shared.
"How bloody amazing!!!! I never knew my wife was a superhero … What a woman!!"
The reality TV star couple shared that they were expecting in May 2020 via Instagram.
"It's been so hard to keep this a secret, over the past few months, but I can now finally shout … I'M PREGNANT!!!" shared Anna.
"With everything that's going on in the world we feel incredibly lucky and grateful to be starting a family together, and we're so looking forward to this next chapter in our lives."
In June, the former criminal lawyer told Stella she struggled with her pregnancy because of Tim's filming obligations with Neighbours. As the couple are based in Sydney, the former chiropractor had to travel to and from the Melbourne set which became difficult because of Covid restrictions.
"It's been really hard. It was hard enough being apart during the weeks when Tim could fly back on weekends; we've really been having a long-distance relationship for two years now," Anna said.
"The past six weeks have been really stressful, it's been one curveball after another and when hotel quarantine came in, we realised it meant that if there was an emergency Tim would not be able to get back to me. That is not risk he is willing to take.
"It was a really hard decision for him to make. He wanted this role and was so happy when he got it. It's a big thing for him to walk away from it and not see it through to the end."
After meeting on The Bachelor in 2013, the couple tied the knot in 2018 and their luxurious Italian wedding made them the first couple from an Australian reality TV franchise to marry. Since then, former Bachelorette duo Georgia Love and Lee Elliott and Bachelor couple Matthew "Matty J" Johnson and Laura Byrne and have also announced their engagements.