Donald Trump Jr. and his wife welcome baby No. 4

Donald Trump Jr. and his wife, Vanessa, are parents to a newborn son.

The couple announced the baby news via Twitter on Sunday:

"It's a BOY!!! @MrsVanessaTrump and baby are doing great," Trump Jr. tweeted. He later noted, "Yea it should be a zoo but very fun!!!"

No name or measurement details were given.

The baby boy is the fourth child for the Trumps, who are already parents to daughter Kai, 5, and brothers Donald Trump III, 3, and Tristan, 1.

Trump Jr. recently joined his father on tapings for the upcoming all-star season of "The Celebrity Apprentice."