Jill Duggar and Derick Dillard have revealed the gender of their first child in a major announcement on Tuesday.

In an exclusive with People.com, the loved-up pair confirmed they are having a baby boy and they could hardly contain their delight.

Jill, who is at 18 weeks, said there was "screaming in the room" when they got the news.

"I thought all along we were having a girl. Everyone made their guesses," she said.

Derick, 25, meanwhile already appears to have visions of their son being the first of many and an example for his future siblings.

"I was really excited," he said. "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."

The couple also revealed they were praying the night before the ultrasound and more important than the gender, their biggest wish was that the baby would be healthy.

"I was praying for a big, healthy baby," said Derick.

They may be just months away from being parents to their precious bundle of joy, but Jill showed the two are still kids at heart themselves.

She shared a fun snap from a shopping trip together on her Instagram page.

The 19 Kids and Counting stars announced they were expecting their first child just weeks after they tied the knot in June and since then have been keeping fans regularly updated with 'Baby Dilly's progress.

They've also been looking to God for inspiration and Jill recently shared some Bible verses "for encouragement during pregnancy, labor and delivery!".

They included Isaiah 26.3: "You keep him in perfect peace whose mind is stayed on you, because he trusts in you."

They also have a gift registry open for Baby Dilly that includes vintage floral cribbing and everyday items like bibs and pacifiers.