Donald Trump Jr. and Vanessa Haydon Trump Donald Trump Jr. and Vanessa Haydon Trump

Donald Trump Jr. and wife Vanessa welcomed their third child on Sunday, the Celebrity Apprentice judge announced on Twitter.

Tristan Milos Trump was born at 2:59 a.m. on Oct. 2, weighing 8 lb., 4 oz.. He joins older sister, 4-year-old Kai Madison, and older brother, 2-year-old Donald John Trump III.

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"Mom and baby doing great! He can't wait to meet his big brother & sister," Trump Jr., 33, wrote on Monday.

"I am delighted that Don and Vanessa have a beautiful new member of their growing family," grandfather Donald Trump told People.

The couple, who have been married since 2005, announced they were expecting in March.