Bindi Irwin has opened up about the “psychological abuse” she has received from her estranged grandpa Bob Irwin on social media, saying that the relationship has negatively affected her mental health.

To celebrate Father’s Day in the US, Bindi Irwin shared a heart-felt post on Facebook acknowledging the three amazing fathers in her life: her dad Steve, husband Chandler and father-in-law Chris .

“Appreciation post for the three most incredible fathers in my life,” Bindi wrote on Facebook.

However, one commenter couldn’t help but notice how Bob Irwin (Steve Irwin’s father) was excluded from the post.

“What about your grandfather you know your fathers, father!!! He too was a good man, who I assume got the shaft,” they wrote.

Bindi then explained why her grandfather is no longer part of her life, due to years of “mental abuse” which has brought the 22-year-old mother “enormous pain.”

“I really wish that my entire family could spend time with Grace. Unfortunately my grandfather Bob has shown no interest in spending time with me or my family,” she said.

“Publicly he continues to claim that he wants to spend time with us while privately my entire life has been psychological abuse from him.”

Despite this rift, Bindi explained that the family still send Bob funds every week after he retired from Australia Zoo in 1992. In 2008, Bob distanced himself from the Zoo entirely.

“I just felt that it was better for everybody concerned if I left Australia Zoo and Judy and I and all our friends were able to continue Steve’s work the way I believe it should be done,” Bob Irwin said on an episode of Australian Story in 2008.

Bindi also confirmed this rift on the Australian Academy of Cinema and Television Arts Awards (AACTA) red carpet in 2015: “Everyone deals with grief differently. When my dad passed away, he [Bob] chose to distance himself from everything that Dad loved the most.”

Many people have shown Bindi support in the comments, and applauded her for setting boundaries and doing what was best for her family.

Love you, Bindi.

Image: Getty Images / Bradley Kanaris