If all the Duggar grandkids were to start their own show, it would be called "4 Grandkids and Counting," jokes 19 Kids and Counting patriarch Jim Bob Duggar.

Jim Bob and his wife Michelle created a "very special" thank you video to all their fans after the arrival of their latest grandson, Israel David Dillard, the first born son of their daughter Jill and her husband Derick.

"We want to thank everybody for all their support for Jill and Derick," said Jim Bob. His wife quickly added: "And for your prayers. What a blessed time this is as we welcome our new grandbaby little Israel into the world, and we are just so thankful to our friends and those out there who have been praying for our family. Thank you so much."

That was when Jim Bob quipped that they now have "four grandkids and counting," and said that he wants the number to go up to a hundred!

Their first grandchild was Josh and Anna Duggar's daughter Mackynzie, followed by two grandsons Michael and Marcus. Israel David, also nicknamed Baby Dilly came in fourth, and he will be followed shortly by Josh and Anna's fourth child - another daughter.

Jim Bob and Michelle earlier shared their joy over Baby Dilly's arrival by posting a message on the Duggar Family blog. "Our sweet new grandson, Israel David Dillard is here. We love him so much already and we love his name!" they wrote. "Our Jill is doing wonderful and Derick seems to have a permanent smile on his face now! Israel is precious and his arrival is just another reminder of how very precious life is and how every child is a gift from God. We are happy grandparents!"

Baby Dilly was born on April 6 at 11:49pm., and he weighed 9 lbs and 10 oz. He arrived just 11 minutes short of two weeks past his due date.