Tv tycoon Donald Trump is a grandfather again after his eldest son welcomed a fourth child.

The Apprentice star's son Donald Trump, Jr.'s wife Vanessa gave birth to the couple's latest addition on Sunday (21Oct12) - a year after their son Tristan Milos was born on 2 October (11).

Taking to Twitter.com to announce the news, Trump, Jr. writes, "It's a Boy!!! Vanessa and baby are doing great."

The couple is also parents to daughter Kai Madison and eldest son Donald John Trump Iii.