Bindi Irwin on Grandpa from Hell: 'It Breaks My Heart'

This Father's Day, Bindi Irwin took to Instagram to praise the three most important dads in her life, but things took a sharp turn when she was asked about her 81-year-old grandfather.

Posting three lovely family photos, Bindi wrote, "Appreciation post for the three most incredible fathers in my life. My dad, my husband and my father-in-law. My dad taught me the importance of strength when standing up for what I believe in and to have empathy for all living beings. My husband amazes me every day with his kind and steadfast heart, his love for our daughter is infinite. My father-in-law works tirelessly for his family and is always there with a word of encouragement. These extraordinary men inspire me and I love them so very much."

TMZ reports that Bindi's take on her late dad's father, Bob Irwin, could not have been more different.

Branding their relationship "abusive," she revealed, “He has returned gifts I’ve sent him after he opened them, he has ignored my correspondence and from the time I was a little girl he has ignored me, preferring to spend time doing anything else rather than being with me.”

Though her mom, Terri, has tried to make things work, Bindi reported, “He has never said a single kind word to me personally. It breaks my heart but it is not healthy to engage in an abusive relationship.”

In fact, though Bindi asserted that her family has supported Bob financially for decades, he hasn't even been photographed with his own granddaughter since a 2007 memorial service for her dad.