Jill Duggar and Derick Dillard are expecting a baby boy!

Duggar and Dillard, who both star on the hit TLC reality TV show "19 Kids and Counting," announced this past August that they are expecting their first child together. And just this Saturday, Oct.18, the couple - accompanied with three of Jill's siblings: Joy Duggar, 16, James Duggar, 13 and Jenny Duggar, 7 - had their gender-revealing ultrasound.

"There was some screaming in the room," Jill, 23, who is 18 weeks along as of Tuesday, Oct. 21, revealed to People. "I thought all along we were having a girl. Everyone made their guesses."

"My mom and dad both thought it was going to be a boy and my grandma did, too," added Jill, who is the fourth-eldest child in the expansive Duggar family. "They are all really excited."

"As a new dad, to have a firstborn son to be our first child and be the leader of his siblings, it is very special," said Derick.

"I was praying for a big, healthy baby," the 25-year-old dad-to-be told the celebrity and entertainment magazine the night before their ultrasound appointment. "And Jill added, 'Just healthy, healthy.'"

But Jill explained that it is likely that their upcoming bundle of joy would be a "giant." "I called Derick's mom and she was telling me that when Derick was born, he didn't fit into the newborn clothes and his shoes were a size two," she said.

When asked if they have already talked about names yet, Jill said, that they "are not going to do a letter theme." "But we may do some kind of theme, like family names," she explained.

Jill told Us Weekly last month that she took three pregnancy tests to determine if she was really expecting.

"I was thinking that maybe we should take a pregnancy test," she told the publication last month. And while the results of her first two tests were negative, the third test turned positive."We were really surprised when we got that positive test, but of course we were really excited. I think we would have even been less surprised had it come back positive on one of the first tests."

The couple's first baby, which is due in March, is definitely not their last, as the two want more kids.

"I have loved having lots of brothers and sisters and although Derick comes from a family with just one brother, both of us would love to have as many children as God will give us," Jill recently told The New York Post's Page Six last month. "We are also open to the possibility of adoption."