Prince Frédéric Prinz von Anhalt knows he isn't getting any younger, and wants some grandkids from his adopted son ... fast!
We got the Prince -- widower of Zsa Zsa Gabor -- leaving Wally's in Bev Hills ... out with his newly-adopted son, 27-year-old Kevin Feucht.
We asked if there was a deadline for Kevin to tie the knot, and Prinz responded quickly -- "tomorrow!" Seems pretty serious ... especially when time isn't on his side.
As you'll recall, the Prince recently adopted Kevin to preserve his royal lineage and inherit his estate when he dies. Anhalt had no children, so this was the next best option.
In early February, we got Prinz in Bev Hills and he told us the adoption isn't a done deal ... if Kevin doesn't prove to be much help, he could be dropkicked stat! "If he is bad, I get another one ... I can adopt as much as I want!"
Hopefully, Kevin doesn't disappoint his new father ... but that first task is a big one -- get married and produce some grandkids.