Vanessa, Donald Trump Jr. Expecting Fourth Child

Vanessa Trump and Donald Trump Jr. on May 5, 2011 in New York City. Credit: Sonia Moskowitz/Getty Images

The Trump family is expanding!

Donald Trump Jr. and his wife Vanessa Trump are expecting their fourth child together.

"Well, Vanessa & I have some good news we are expecting baby num 4 in the fall!!!" Trump Jr. tweeted Wednesday evening. "Kai, Donnie, & Tristan can't wait!"

The couple, who married in 2005, are already parents to daughter Kai, nearly 5, son Donald III, 3, and Tristan Milos Trump, 6 months.

When baby Tristan was born Oct. 2 of last year, grandfather Donald Trump told Us Weekly, "I am delighted that Don and Vanessa have a beautiful new member of their growing family.