"With her mother's hardware and her Dad's software (so I'm told) we could be in for a wild ride the next 20 odd years! Wish us luck haha!" Tim finished.
Celeb friends of the couple quickly flooded the comment section with love for little Elle.
"Ohh happy birthday Elle! And well done Anna - I reckon getting through the first year is even bigger for the parents!!!" Jess Rowe wrote.
"Gorgeous! Happy birthday! 🎉💜" shared fitness influencer Lauren Hannaford.
"Happy Birthday 😊" wrote Barry Hall, who also just became a dad for the third time.
Tim and Anna are well-known to us as Australia's OG Bachie couple, having met and fell in love on the very first Australian season of the show, in 2013.
A chiropractor living in Sydney at the time, Tim hit it off with Anna, who was a 26-year-old lawyer at the time she joined the show.
Their winning romance captured hearts across the nation, giving them a public profile that they've used ever since to pursue a range of different opportunities.
Anna recently filmed for the new season of reality show SAS Australia, which will air next year, while Tim has dabbled in acting and fitness.
The pair married in 2018 at a dreamy ceremony in Italy, with Elle coming along two years later.
They work hard to balance their parenting commitments together as Elle grows.
"Whenever I need to go out for a run, or whenever I need a sleep in, he's there to help," Anna told Now to Love earlier this year.
"Each day if possible, I'll take a bit of me time. This can be as simple as just taking a shower on my own, I kid you not," she told The Daily Telegraph.
"This has finally, after a number of weeks, become a priority, as soon as I started to do more for me, I became a better mum to Elle."