updated 07/04/2010 AT 2:45 PM ET
•originally published 07/04/2010 AT 12:05 PM ET
If Matt Damon wants to find out anything about his wife’s pregnancy he just needs to ask their kids.
“They track its progress in mommy’s belly,” he said Saturday while attending the Ante Up for Africa charity poker event in Las Vegas.
His wife, Luciana, is set to deliver the couple’s fourth child this fall. They currently have three daughters: Alexia, 11, who is Luciana’s child from a previous marriage, Isabella, 4, and Gia, 22 months.
The kids “are very excited” about another addition to the family, Damon, 39, said.