Donald Trump Jr. and wife Vanessa Trump announced on Twitter Jan. 21 that they are expecting their fifth child together; the baby-to-be will be Donald Trump Sr.'s seventh grandchild. Credit: Virginia Sherwood/NBC/NBCU Photo Bank

The Trump family keeps getting bigger! Donald Trump Jr. announced on Twitter Tuesday, Jan. 21 that he and wife Vanessa Trump expecting their fifth child together.

"Well @MrsVanessaTrump, Kai, D3, T-man Spencer & I have some exciting news," Trump Jr. wrote. "We are expecting baby #5 this summer. Cant wait #evenlesssleep," he jokingly added.

Fifth-time mom-to-be Vanessa also tweeted, "We are very excited!"

UPDATE: "We are thrilled to be welcoming baby number 5 this summer!" Trump Jr. exclusively tells Us Weekly. "Vanessa and I can't wait to continue the adventure of raising the big family we have always wanted and have been blessed to receive."

Trump Jr., 36, who is the eldest son of Donald Trump and first wife Ivana Trump, married model Vanessa in November 2006. They are parents to daughter Kai, 6, and sons Donald John Trump III, 4, Tristan, 2, and Spencer, 15 months.

This will be Donald Trump's seventh grandchild. Donald Trump Jr.'s younger sister Ivanka Trump, 32, is mom to daughter Arabella, 2, and son Joseph, 3 months, with husband Jared Kushner.