Beloved animal and wildlife expert, Jack Hanna, has been diagnosed with dementia, his family announced on Wednesday, April 7.

The 74-year-old star’s daughters, Kathaleen, Suzanne and Julie disclosed their father’s diagnosis, while also explaining that he will be stepping away from the spotlight due to his illness.

“Doctors have diagnosed our dad, Jack Hanna, with dementia, now believed to be Alzheimer’s disease,” Jack’s family wrote in a statement that was shared on the star’s official Twitter account. “His condition has progressed much faster in the last few months than any of us could have anticipated.”

“Sadly, Dad is no longer able to participate in public life as he used to,” their statement continued, “where people all over the world watched, learned, and laughed alongside him.”

The wildlife expert rose to fame after frequently appearing—with exotic animals no less—on talk shows such as The Tonight Show Starring Johnny Carson, Good Morning America, Late Night with David Letterman, Maury and many others.