"We actually got out of the gym, because we wanted to try and replicate what she would go up against in the real world of SAS," Tim, 39, tells WHO.
"I was really trying to go, what will you be up against? Well, you’ll be carrying a backpack, climbing up things, there’s going to be cold and icy water, you’ll be out in the rain. All of those things.
"She’d be running the hills of Bellevue Hills with a backpack on, with me pushing Elle in a pram."
Anna says it was all about "getting comfortable with being uncomfortable" as she prepped for the notoriously brutal challenge.
Much like Jana Pittman, who competed on the show this year, Anna began training for the show just a few months after Elle was born. With filming kicking off in October, Anna was competing on the show 11 months after giving birth.
"Tim encouraged me [to do the show]. It was definitely something I never thought I’d be doing, there was just no way. It’s so far out of my comfort zone," Anna admits.
Saying he may have been living a little vicariously through his wife, Tim reveals his unwavering support and admiration for Anna.
"I know how strong Anna is. How resilient she is and how much inner strength she has, and I knew if she decided to set her mind to it she would give it everything," Tim says.
"Maybe I was also living a little vicariously through her, but I knew she would do well because she’s got the fitness and the heart and the underlying drive to really push herself."
When the new cast was confirmed in October, Tim revealed on Instagram that he'd been working out with Anna.
"So proud of my girl for going ALL IN on this," the star wrote on Instagram. "However she goes it’s been such an incredible journey even to this point."
"The training we’ve been able to do together, even with Elle in tow, has been an incredibly empowering and belief building journey for Anna by itself, and brought us even closer as a family in lockdown. Winning already," Tim continued his post.
The Neighbours star went on to admit he's "enjoyed" bossing Anna around as they train - boxing together to work on her strength.
"I must admit though I have enjoyed ordering her around and shouting ‘get up and go again!, but I won’t miss the blows to the head she’s been delivering in our boxing training," he writes.
"Whatever happens Daddy and Elle are extremely proud, slightly jealous, but also slightly relieved that it’s not us."
The star will be joined on SAS: Australia by fellow Bachelor alumni Locky Gilbert, Real Housewives of Sydney star Melissa Tkautz, Home and Away star Orpheus Pledger and rugby league player Ellia Green.