Fans praised Georgia for nailing such a surprise so quickly after their wedding earlier this month.
"You’re amazing Georgia. To organise this on top of your wedding AND to keep it a surprise... You guys are too cute," one remarked.
"U guys know how to celebrate! Happy Amazing Birthday Lee," penned another.
"You guys really have had the best few weeks, love how much fun and happy you always are," a third noted.
Lee shared his own post and captioned it: "Growing old is inevitable, but growing up is optional. #naughtyforty"
"Cracking day. Happy 28th," friend Rob Mills joked on Lee's post.
Another follower penned: "Ahh what a perfect birthday surprise! Happy 40!!"
Lee and Georgia, who met and fell in love in 2016 whilst filming The Bachelorette, tied the knot in Tasmania in early March.
The new Mrs Elliott has been delighting fans with her photos and recently shared a sweet insight into her and Lee's special day when she uploaded a sneak peek of their wedding video.
"I can’t understand why some brides say the ceremony is nerve-wracking, it was honestly SO MUCH FUN!!!" she exclaimed on Instagram.
"I was smiling so large Lee thought my face was going to burst open and I kept stopping to wave to people and say 'Aahh this is so fun!!' so much our celebrant @marriedbybob had to keep stopping and waiting for me to pay attention."