"Dad, you would be so incredibly proud of Robert. He has been such an amazing support during this beautiful new life chapter," Bindi wrote on Friday, alongside family photos. "I know you’d be beaming with pride when the time comes that he walks me down the aisle. I wish you could be here for these moments, but I know that your spirit lives on in us ❤️."
"I think that for me, it'll be really important that Robert walks me down the aisle," Bindi shared. "That's something that I really want to do."
Bindi admitted that there was a certain "bittersweet" element to the special moment. "It was so incredibly special. But then, at the same time for me on a personal note, there's people who I really wish could be here today for this time in my life," she shared. "Particularly my dad."
"I wish that he could be here to be getting excited and welcome [Chandler] into the family, and I think that's really challenging [for me]," Bindi explained. "I think that Dad would have loved him so much and he would have been so excited that he's now part of our family."
See more of ET's exclusive interview with the pair in the video below.