Not just any grandfather - the BEST grandfather in the world.
Indeed, the elder Donald Trump is set to welcome his first grandchild into the world now that Donald Trump Jr. and his wife of one year, Vanessa, are expecting their first kid.
"Everyone's very excited," Vanessa, 28, told People magazine. Although "if you mention the 'grandpa' word (to Donald Sr.), he might not be so excited."
Mention Kevin Federline to him, however, and the Donald has a lot to say.
Of course, Trump and his wife, Melania, recently had a son named Barron. So the offspring of Donald Jr. will be just a year or so younger than his uncle. It's complicated stuff - and Caroyln Kepcher isn't around anymore to help sort it out.
"They'll be more like brothers, or brother and sister," said Vanessa, who wants her baby's sex to be a surprise.
Meanwhile, Vanessa wants a big family according to Junior.
"She (wants) five," Don said. "I'll wait till she cranks out one and then I want to renegotiate that back a bit."