Prince Frédéric Prinz von Anhalt Adopting Adult Son To Preserve Lineage

Frédéric Prinz von Anhalt, AKA the widower of actress Zsa Zsa Gabor, needed a new heir to inherit his estate and preserve his royal lineage ... so he chose to adopt someone -- an adult!

That's right, 78-year-old von Anhalt has no children. So he'll be adopting 27-year-old Kevin Feucht.

And, it's the real deal ... Apparently, Kevin's dad had been friends with Frédéric, now Kevin has officially changed his last name on his birth certificate and will be living with his new father.

Kevin says his former parents are all good with it, and they'll all remain friends.

Kevin's new last name will come with a few responsibilities. He agreed to take care of Frédéric ... he'll be helping out his new father by cooking for him, doing chores around the house and making sure his bills are paid on time.

It's interesting because Frédéric was also adopted by a well-known princess in Germany when he was 35 ... which is how he became a prince.

Now, he will be passing that legacy on to Kevin, who is also German. Kevin's a graduate of UC Santa Barbara, and now owns a soccer training center. He says he's excited to build onto the legacy and make it even bigger.

Zsa Zsa met Frédéric at a party in L.A., and they got married 3 years later ... she passed away back in 2016.

Frédéric says he wanted to make the quest for his new son public.