Donald Trump Jr. and wife expecting fourth child

(CBS News) There's another little Trump on the way.

Donald Trump Jr. and his wife, Vanessa, are expecting their fourth child, he announced Wednesday.

Pictures: Celebrity baby bumps

"Well, Vanessa & I have some good news we are expecting baby [number] 4 in the fall!!!" he tweeted. "Kai, Donnie, & Tristan can't wait!"

The new arrival and the couple's third child will be close in age.

"They'll be 13 months apart, Irish twins!" he added.

The couple are already parents to daughter Kai Madison, who will turn 5 next week, and sons Donnie John III, 3, and Tristan Milos, 7 months.