Bindi Irwin’s grandfather won’t be coming to her 16th birthday. A new report claims that an old family rift has hindered animal conservationist Bob Irwin from attending his granddaughter’s huge birthday party at the Australia Zoo in July.

On July 24, the Australia Zoo is planning to break the record for the “world’s biggest onesie party” with free admission to the public. This will be in celebration of Bindi’s 16th birthday.

Bindi’s family will naturally be there, including her mum Terri and her 10-year-old brother Robert.

Grandpa Bob won’t attend the celebration, though.

“In actual fact I’ll be in Cape York, so I won’t be there,” he told 9 Stories.

It’s not clear whether or not Bob was invited personally. A spokeswoman for Australia Zoo said that “everyone’s invited” to the party.

According to speculations, Bob, the father of the late Crocodile Hunter Steve Irwin, perhaps hasn’t seen his grandchildren yet.

In 2010, he revealed that his feud with Terri had prevented him from seeing Bindi and Robert.

“I haven’t heard from them (Bindi and Robert) and it is sad but that is a part of life, I guess,” he had told The Sunday Telegraph then.

Apparently, Bob was upset by the commercial direction Terri was taking the Australia Zoo. He had quit Australia Zoo in 2008 in controversial circumstances, with zoo staff and volunteers claiming he had a falling out with his son’s widow.

That feud went on even after the 74-year-old suffered a heart attack two years later, and his grandkids weren’t able to visit him.

Bob refused to say whether the family rift has been resolved or if Bindi and Robert have visited him in the past years, only saying that he “keeps in contact with family members on a regular basis.”

“I think Terri’s done a great job with those children, she’s had to raise them herself,” he said.

“They are well adjusted children – they have a good background with their dad. Nobody could be more down to earth than Steve was.

“They’ve got a great future ahead of them.”

Steve died in 2006 after a stingray pierced him in the chest while he was filming an underwater documentary.