Enthusiastic fans were quick to comment on the snap, with one fan writing: “That must be fun and awkward.”
Another person stated: “Super cute!! At least they get to honeymoon at a Zoo!! That must be pretty cool!!”
A third person added: “Haha!! This is the ONLY time that would be acceptable!!”
While it may appear as though Rob was third wheeling, it’s highly likely the teenager was joking with his sister, as he and Bindi share a family bond that is particularly strong.
Since their late father Steve died in 2006, Robert stepped up and was the one to walk Bindi down the aisle on her wedding day.
"Walking my sister down the aisle was one of the most special moments of my life," Robert wrote on Instagram shortly after the wedding.
"Bindi, you are the most amazing sister and friend, always there for me through it all and I just couldn’t be happier you found Chandler. And Chandler, I am so happy to now welcome you into our family as my brother. March 25 was a truly beautiful day!"
Chandler also shared some details of how he and his new wife are spending their first months of married life.
The 23-year-old former wakeboarder shared a photo of himself and Bindi at the Queensland zoo alongside one of their many furry friends.
"How we spend ‘koala-ty’ time together as husband and wife... Love the friendly #AustraliaZoo residents coming over to say, 'G’day'! We have the best wildlife family in the world," he captioned his post.
Bindi and Chandler became husband and wife in March, just hours before the Australian government enforced a shutdown on weddings with more than five people in attendance.